#include <bits/stdc++.h>
using namespace std;
int n, h, m = 0, ans = 0, a[111111], b[111111];
int main() {
  scanf("%d%d", &n, &h);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &a[i], &b[i]);
    m = max(m, a[i]);
  }
  sort(b + 1, b + n + 1);
  for (int i = n; i && b[i] > m; i--) {
    h -= b[i];
    ans++;
  }
  if (h > 0) {
    ans += (h + m - 1) / m;
  }
  printf("%d", ans);
  return 0;
}
