#include <iostream>
#include <string>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <numeric>
#include <cmath>

using namespace std;

typedef long long int ll;
typedef pair<int,int> P;

#define all(x) x.begin(),x.end()

const ll mod = 1e9+7;
const ll INF = 1e9;
const ll MAXN = 1e9;

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

    return 0;
}