#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>

#include <atcoder/all>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    int n = v.size();
    rep(i, 0, n) { os << v[i] << " \n"[i == n - 1]; }
    return os;
}

void solve() {
    int n, m;
    cin >> n >> m;
    vector<int> a(n), b(n), d(n);
    rep(i, 0, n) {
        cin >> a[i] >> b[i];
        d[i] = (m - a[i]) / b[i];
    }
    // cout << d;
    sort(d.begin(), d.end());
    auto check = [&](ll mid) {
        vector<int> e(n);
        int cur = -1;
        rep(i, 0, n) {
            if (i % mid == 0) cur++;
            e[i] = cur;
        }
        rep(i, 0, n) if (e[i] > d[i]) return 0;
        return 1;
    };
    auto binary = [&]() {
        ll ac = n + 1, wa = -1;
        while (llabs(ac - wa) > 1) {
            ll mid = ac + (wa - ac) / 2;
            if (check(mid)) {
                ac = mid;
            } else {
                wa = mid;
            }
        }
        return ac;
    };
    cout << binary() << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    while (t--) solve();
}