推公式

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <queue>

using namespace std;

int n, L, R;

int main() {


    cin >> n >> L >> R;

    if (L / n == R / n) cout << R % n << endl;
    else cout << n - 1 << endl;




    return 0;
}