#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int w[n], t[n], st = 0, nt = 0, lw = 0;
  for (int i = 0; i < n; i++) {
    cin >> w[i] >> t[i];
    if (w[i] >> lw) lw = w[i];
  }
  for (int i = 0; i < n; i++) {
    if (t[i] > lw) {
      st += t[i];
      nt++;
    }
  }
  int nw = (h - st) / lw;
  int katanas = nw + nt;
  if (nw * lw >= h - st)
    cout << katanas;
  else
    cout << katanas + 1;
  return 0;
}
