#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
using namespace std;


int main()
{
    int l, r, m, ans;
    cin >> l >> r >> m;
    if ((ans = r - l + 1) >= m) cout << m << endl;
    else cout << ans << endl;
}