#include "bits/stdc++.h"
#define in std::cin
#define out std::cout
#define rep(i,N) for(LL i=0;i<N;++i)
typedef long long int LL;

int main()
{
	LL L, R, M;
	in >> L >> R >> M;
	out << std::min(R - L + 1, M) << std::endl;
}