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

using i32 = int;
using i64 = long long;
using i128 = __int128_t;
using f64 = double;
using p2 = pair<i64, i64>;
using el = tuple<i64, i64, i64>;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
  _main();
}

void _main() {
  i64 n, m;
  cin >> n >> m;
  vector<i64> t;
  for (i64 i = 0; i < n; i++) {
    i64 a, b;
    cin >> a >> b;
    i64 d = (m - a) / b;
    t.push_back(d);
  }
  sort(t.begin(), t.end());
  i64 l = 0, r = n;
  while (r - l > 1) {
    i64 mid = (l + r) / 2;
    bool ok = true;
    for (i64 i = 0; i * mid < n; i++) {
      i64 j = i * mid;
      ok &= t[j] >= i;
    }
    if (ok) r = mid;
    else l = mid;
  }
  cout << r << "\n";
}