#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll =  long long ;
using P = pair<int,int> ;
const int INF = 1e9;
const int MOD = 1000000007;

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