#include <bits/stdc++.h>
using namespace std;
int N, H, a[100001], b[100001], ans;
int main() {
  scanf("%d %d", &N, &H);
  for (int i = 1; i <= N; ++i) {
    scanf("%d %d", &a[i], &b[i]);
  }
  sort(a + 1, a + N + 1);
  sort(b + 1, b + N + 1);
  for (int i = N; i > 0; --i) {
    if (b[i] <= a[N]) break;
    H -= b[i];
    ++ans;
    if (H <= 0) break;
  }
  ans += (H + a[N] - 1) / a[N];
  printf("%d\n", ans);
}
