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

using ll = long long;
using vi = vector<ll>;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int n;
	ll M;
	cin >> n >> M;

	vi a(n), b(n);
	for (int i = 0; i < n; ++i) cin >> a[i] >> b[i];

	ll l = 0LL, r = (M + b[0]) / a[0] + 1LL;
	while (l < r) {
		ll m = (l + r) / 2LL, p = 0LL;
		for (int i = 0; i < n; ++i) {
			ll t = a[i] * m - b[i];
			p = min(M, max(p, p + t));
		}
		if (p < M)
			l = m + 1;
		else
			r = m;
	}

	cout << l << endl;

	return 0;
}