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

void just_do_it();

int main() {
	#ifdef KAMIRULEZ
		freopen("kamirulez.inp", "r", stdin);
		freopen("kamirulez.out", "w", stdout);
	#endif
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	just_do_it();
	return 0;
}

long long P, delta;
long long cur_x, cur_y;
__int128 sum;

bool inside(long long x, long long y) {
	return (((__int128)x * x + delta) / P) < y;
}

void build(long long a, long long b, long long c, long long d) {
	long long e = a + c;
	long long f = b + d;
	if (cur_x < e || cur_y < f) {
		return;
	}
	if (inside(cur_x - e, cur_y - f)) {
		build(a, b, e, f);
	}
	else if ((__int128)P * d >= (__int128)2 * (cur_x - e) * c) {
		return;
	}
	if (cur_x < e || cur_y < f) {
		return;
	}
	if (inside(cur_x - e, cur_y - f)) {
		long long lt = 1;
		long long rt = min(cur_x / e, cur_y / f);
		while (lt <= rt) {
			long long mt = (lt + rt) / 2;
			if (inside(cur_x - e * mt, cur_y - f * mt)) {
				lt = mt + 1;
			}
			else {
				rt = mt - 1;
			}
		}
		long long k = rt;
		long long nxt_x = cur_x - e * k;
		long long nxt_y = cur_y - f * k;
		sum += (__int128(cur_y + nxt_y) * (cur_x - nxt_x) - (cur_y + nxt_y + cur_x - nxt_x + k)) / 2 + cur_y;
		cur_x = nxt_x;
		cur_y = nxt_y;
	}
	if (cur_x < c || cur_y < d) {
		return;
	}
	if (inside(cur_x - c, cur_y - d)) {
		build(e, f, c, d);
	}
}

void calc() {
	cur_x = (P - 1) / 2;
	cur_y = ((__int128)cur_x * cur_x + delta) / P + 1;
	sum = 0;
	build(0, 1, 1, 0);
}

void just_do_it() {
	long long L, R;
	cin >> P >> L >> R;
	delta = P - L;
	calc();
	__int128 sum1 = sum;
	delta = P - R - 1;
	calc();
	__int128 sum2 = sum;
	long long res = sum1 - sum2;
	cout << res;
}