#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int n, h;
int a[maxn];
int b[maxn];
int cmp(int x, int y) { return x > y; }
int main() {
  cin >> n >> h;
  int mx = 0;
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &a[i], &b[i]);
    mx = max(a[i], mx);
  }
  sort(b, b + n, cmp);
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (b[i] < mx || h <= 0) break;
    ans++;
    h -= b[i];
  }
  if (h) ans += ceil((double)h / mx);
  cout << ans << endl;
  return 0;
}
