'''Add, subtract

Implement the function
execute(code: str) -> str 
in addition to the properties of the previous functions, the following additional commands:


INC variable number
The command adds the given integer to the given variable. The value of the variable is thus incremented by the given number.

DEC variable number
This command decreases the given variable by the given integer. The value of the variable is therefore decreased by the given number.

INC variable1 variable2
The command adds the value of variable 2 to the value of variable 1. The value of variable 1 is thus increased by the value of variable 2.

DEC variable1 variable2
The command decreases the value of variable 1 by the value of variable 2. The value of variable 1 is therefore decreased by the value of variable 2.



Example programs for testing:

Program:
LET a=20
INC a 10
PRINT a
The program returns the output:
30




Program:
LET a=100
LET b=150
DEC a 50
DEC b 200
PRINT a
PRINT b
The program returns the result:
50
-50




Program:
LET a=100
LET b=50
DEC a b
PRINT a
PRINT b
INC a b
PRINT a
The program returns the result:
50
50
100




Program:
LET d=1000
LET a=100
LET b=10
LET c=1
INC d a
INC d b
INC d c
PRINT d
DEC d a
DEC d b
DEC d c
PRINT d
The program returns the result:
1111
1000
'''






def execute(code: str) -> str:
    variables = {'a': 0, 'b': 0, 'c': 0, 'd': 0}
    output = []
    
    for line in code.split('\n'):
        line = line.strip()

        #########################
        # round 2 - Skip empty lines
        if not line:
            continue
        #########################
        
        if line.startswith('LET'):
            _, assignment = line.split(' ', 1)
            var, value = assignment.split('=')
            if var in variables:
                variables[var] = int(value)
            else:
                raise ValueError(f"Invalid variable name: {var}")
        elif line.startswith('PRINT'):
            _, var = line.split()
            if var in variables:
                output.append(str(variables[var]))
            else:
                raise ValueError(f"Undefined variable: {var}")




        ##########################################
        # 19. part 2
        ##########################################
        elif line.startswith('INC') or line.startswith('DEC'):
            # Handle INC and DEC commands
            parts = line.split()
            command = parts[0]
            var1 = parts[1]
            
            if var1 not in variables:
                raise ValueError(f"Invalid variable name: {var1}")




            if len(parts) == 3:
                # Check if parts[2] is an integer
                try:
                    value = int(parts[2])  # Try to convert parts[2] to an integer
                    
                    # If conversion succeeds
                    # INC/DEC variable number
                    if command == 'INC':
                        variables[var1] += value
                    elif command == 'DEC':
                        variables[var1] -= value



                        
                # parts[2] is NOT an integer
                except ValueError:
                    # INC/DEC variable1 variable2
                    var2 = parts[2]
                    if var2 not in variables:
                        raise ValueError(f"Invalid variable name: {var2}")
                    
                    if command == 'INC':
                        variables[var1] += variables[var2]
                    elif command == 'DEC':
                        variables[var1] -= variables[var2]        
            
            else:
                raise ValueError(f"Invalid command format: {line}")
        ##########################################


                
        else:
            raise ValueError(f"Invalid command: {line}")

            

    
    joined_output = '\n'.join(output)
    joined_output+='\n'
    return joined_output






eg1='''LET a=20
INC a 10
PRINT a'''

print(execute(eg1))
30





eg2='''LET a=100
LET b=150
DEC a 50
DEC b 200
PRINT a
PRINT b'''

print(execute(eg2))
50
-50




eg3='''LET a=100
LET b=50
DEC a b
PRINT a
PRINT b
INC a b
PRINT a'''

print(execute(eg3))
50
50
100





eg4='''LET d=1000
LET a=100
LET b=10
LET c=1
INC d a
INC d b
INC d c
PRINT d
DEC d a
DEC d b
DEC d c
PRINT d'''

print(execute(eg4))
1111
1000









'''round 1 - autograder error

Error in program execution
line 110, in
testaa(koodi)
File "/tmp/untrusted/test056323216-d11f-433b-8fcd-7f9f59117650/test.py", line 98, in testaa
lopputulos = execute(koodi)
File "/tmp/untrusted/test056323216-d11f-433b-8fcd-7f9f59117650/test.py", line 82, in execute
raise ValueError(f"Invalid command: {line}")
ValueError: Invalid command:
'''





'''round 2 - autograder 20/20. actual vs expected output (62 lines)
Testing code:

LET a=72
INC a 19
PRINT a

Program outputs:
91

Testing code:

LET a=76
LET b=380

DEC a 13
DEC b 65

PRINT a
PRINT b

Program outputs:
63
315

Testing code:

LET a=72
LET b=10

DEC a b
PRINT a
PRINT b

INC a b
PRINT a

Program outputs:
62
10
72

Testing code:

LET d=3000
LET a=300
LET b=30
LET c=3

INC d a
INC d b
INC d c
PRINT d

DEC d a
DEC d b
DEC d c
PRINT d


Program outputs:
3333
3000
'''