#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <stdio.h>
#include <assert.h>
using namespace std;
#define int long long
signed main() {
	int L, R, M;
	cin >> L >> R >> M;
	assert(0 <= L);
	assert(L <= R);
	assert(R <= (int)1e9);
	assert(1 <= M);
	assert(M <= (int)1e9);
	cout << min(R - L + 1, M) << endl;
}