#include <iostream>
using namespace std;


int main()
{
    int aNumber, bNumber;
    cin>>aNumber;
    cin>>bNumber;


    if(bNumber > aNumber)
    {

        cout<< ((bNumber-(aNumber + (aNumber%2? 0:1) ))/2) + 1;
    }
    else if(bNumber == aNumber)
    {
        cout<<"1";
    }

}

what might be test case #4 ?

Try this:
4 4
The answer should be 0.

Edited by author 02.04.2015 00:59