#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  int a[100000] = {}, b[100000] = {}, s = 0, sum = 0, cnt = 0, cn2 = 0,
      amax = 0;
  cin >> N >> H;
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  for (int i = 0; i < N; i++) amax = max(a[i], amax);
  sort(&b[0], &b[N]);
  for (int i = N - 1; (i >= 0) && (b[i] > amax); (++cn2) && (i--)) s += b[i];
  sum += s;
  while (1) {
    if (sum >= H) break;
    sum += amax;
    cnt++;
  }
  cout << cnt + cn2 << endl;
  return 0;
}
