#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define rep(i,n) for(int i=0;i<n;i++)

const ll mod = ll(1e9) + 7;
const int INF = 1<<29;

int main(){
    int l,r,m;
    cin >> l >> r >> m;
    int ans = min(r-l+1,m);
    cout << ans << endl;
    return 0;
}