#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  vector<pair<int, int>> v(n);
  rep(i, n) cin >> v[i].first >> v[i].second;
  vector<int> d(n);
  rep(i, n) d[i] = (m - v[i].first) / v[i].second;
  sort(d.begin(), d.end());
  int ans = 0;
  rep(i, n) {
    // i + 1 <= k * (d[i] + 1)
    ans = max(ans, (i + 1 + d[i]) / (d[i] + 1));
  }
  cout << ans << '\n';
  return 0;
}