Comparing two integeres bu use of if condition in Python

I have written below code and tried running in python, it works well if I give input as a =56 b = 67, but it gives wrong comparison if input given as a = 789,b =45566 -

Below is the code written

def max(a,b):
    if a>b:
        print(a+" is greater than "+b)

    else:
        print(b +" is greater than "+ a)

o1 = raw_input("Enter value of A ")
o2 = raw_input("Enter value of B ")

to = max(o1,o2)

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Output is if A = 789 , B = 45566 is entered - Enter value of A 789 Enter value of B 45566 789 is greater than 45566