#include<bits/stdc++.h>
using namespace std;

int main()
{
	long long n, l, r, maxn = -1;
	cin >> n >> l >> r;
	for(long long i = l; i <= r; i++)
	{
		long long yu = i % n;
		maxn = max(yu, maxn);
	}
	cout << maxn;
	return 0;
 }