#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-10;
const double PI = acos(-1.0);
int main() {
  int n, h;
  cin >> n >> h;
  pair<int, int> x[200000];
  for (int i = 0; i < n; ++i) {
    cin >> x[i].first >> x[i].second;
    x[n + i].first = x[i].second;
    x[n + i].second = -i;
  }
  sort(x, x + 2 * n);
  int t = 0;
  int po = 2 * n - 1;
  while (1) {
    if (x[po].second < 0) {
      h -= x[po].first;
      po--;
      t++;
    } else {
      t += h / x[po].first;
      if (h % x[po].first) t++;
      break;
    }
  }
  cout << t << endl;
}
