Simple syntax error in if statement [on hold]

Right now I'm facing stupid problem: can't figure out what is this error I get:

File "<ipython-input-21-caf31695922a>", line 8
    if x == 'round' :
                    ^
SyntaxError: invalid syntax

In the following part of my code:

    .....
    print((p*(p-a)*(p-b)*(p-c)**0.5)
if x == 'round' :
    r=input('Input radius')
    ....

What might be wrong here? As for me syntax is fine.