Binary to decimal converter

def bin_dec(binary):
    decimal = 0
    i = 0
    while (binary != 0):
        rem = binary % 10
        last_digit = rem * pow(2,i)
        decimal = decimal + last_digit
        binary = binary // 10
        i += 1
    return decimal

num = int(input("Enter binary number"))
result = bin_dec(num)
print(result)