x = 1  Result = 0
x = 2  Result = 1
x = 3  Result = 1
x = 4  Result = 2
x = 5  Result = 2
x = 6  Result = 3
x = 7  Result = 3
x = 8  Result = 4
x = 9  Result = 4
x = 10  Result = 5