#include <iostream>
#define lsb(x) x & (-x)
#define Nmax 19894
using namespace std;
int aib[Nmax];
int v[Nmax], N;
void update(int pos, int x) {
    for (int i = pos; i <= N; i += lsb(i))
        aib[i] += x;
}
int query(int pos) {
    int ans = 0;
    for (int i = pos; i >= 1; i -= lsb(i))
        ans += aib[i];
    return ans;
}
int main()
{   N = 10;

    update(5, 1);
    update(4, -1);
    cout << query(5) - query(4);
    return 0;
}