#include <bits/stdc++.h>

using namespace std;

int main(int argc, char *argv[]) {
    int64_t L, R, M;
    cin >> L >> R >> M;

    int64_t sub = R - L + 1;
    if (sub >= M) {
        cout << M << endl;
    } else {
        cout << sub << endl;
    }   
    return 0;
}