#include <bits/stdc++.h>
#include <algorithm>
using namespace std;
using ll = long long;
#define overload4(a, b, c, d, name, ...) name
#define rep1(n) for (ll i = 0; i < n; ++i)
#define rep2(i, n) for (ll i = 0; i < n; ++i)
#define rep3(i, a, b) for (ll i = a; i < b; ++i)
#define rep4(i, a, b, c) for (ll i = a; i < b; i += c)
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
void solve();
int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    ll t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) solve();
    return 0;
}
ll dy[4] = {-1, 0, 1, 0}, dx[4] = {0, 1, 0, -1};
void solve() {
    ll n, m;
    cin >> n >> m;
    vector<ll> a(n), b(n);
    rep(i, n) cin >> a[i] >> b[i];
    auto calc = [&](ll x) -> bool {
        vector<ll> c(n);
        rep(i, n) {
            ll rem = m - a[i];
            c[min(n - 1, rem / b[i])]++;
        }
        ll val = 0;
        rep(i, n) {
            if (c[i] > x) {
                if (val < c[i] - x) return false;
                val -= c[i] - x;
            } else {
                val += x - c[i];
            }
        }
        return true;
    };
    ll ok = n, ng = 0;
    while (ok - ng > 1) {
        ll mid = (ok + ng) / 2;
        if (calc(mid)) ok = mid;
        else ng = mid;
    }
    cout << ok << endl;
}