#include <iostream>
using namespace std;
typedef long long ll;

ll n, l, r; 

int main()
{

	ll m = -0x3f3f3f3f; 
	cin >> n >> l >> r;
	for(ll i = l; i <= r; i ++ ){
		if(i > n){
			if(m < i % n) m = i % n;
		}
	}
	cout << m;
	return 0;
}