homework

[NZedMarine]

ArPe = str(input("Area Or Perimeter? "))
print("Ok " + ArPe + " we will calculate"):
    if arpe == "area" or "perimeter":
        x = "true"
    elif arpe == null or int:
        x = false 
    else:
        print("wot have u done?")
print(x)

Error:
  File "/home/main.py", line 2
    print("Ok " + ArPe + " we will calculate"):
                                              ^
SyntaxError: invalid syntax

i dont understand :( help