#include <bits/stdc++.h>
using namespace std;
int a[100001];
int b[100001];
int main() {
  int n, h;
  scanf("%d%d", &n, &h);
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i], &b[i]);
  int maxi;
  int maxval = 0;
  for (int i = 1; i <= n; i++)
    if (maxval < a[i]) {
      maxi = i;
      maxval = a[i];
    }
  int cnt = 0;
  for (int i = 1; i <= n; i++) {
    if (i == maxi) continue;
    if (b[i] > maxval) {
      h -= b[i];
      cnt++;
    }
    if (h <= 0) break;
  }
  if (h > b[maxi]) {
    int temp = (h - b[maxi] + a[maxi] - 1) / a[maxi];
    h -= temp * a[maxi];
    cnt += temp;
  }
  if (h > 0) cnt++;
  cout << cnt << endl;
  return 0;
}
