Timus_1327

//Timus 1327
#include <iostream>
using namespace std;
int main()
{
    int a, b, answ=0;
    cin >> a >> b;
    for(int i=a;i<b+1;i++)
    {
        if(i%2!=0){answ++;}
    }
    cout << answ;
    return 0;
}