#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

int l,r,m;

int main () {
    cin.tie(0); ios::sync_with_stdio(false); 

    cin >> l >> r >> m;
    cout << min((r-l+1),m) << endl;
}