a = input('hour')
b = input('number of hours')
int(a)
int(b)
h = a // 24
s = a % 24
print(h, s)
a = a + s
print( 'hour now', a)

TypeError: unsupported operand type(s) for //: 'str' and 'int' on line 5

On line 5 we are trying to use integer division on a and 24. The error message tells you that you are trying to divide a string by a number. In this case you know that 24 is a number so a must be a string. But how? You can see the function call on line 3 where you are converting a to an integer with int(a). The problem is that the expression int(a) does not assign a to the integer. The proper assignment expression here is a = int(a).