#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;

int L,R,M;

int main(){ 

cin.tie(0);
ios::sync_with_stdio(false);

cin>>L>>R>>M;

if(R-L+1>=M){
	cout<<M<<endl;
}else{
	cout<<R-L+1<<endl;
}

}