#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 7, MOD = 1e9 + 7;
const long long LINF = 1e18;
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int main() {
  int n, h, ans = 0, cmp = 0;
  cin >> n >> h;
  int a[n], b[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n);
  reverse(a, a + n);
  sort(b, b + n);
  reverse(b, b + n);
  for (int i = 0; i < n; i++) {
    cmp += b[i], ans++;
    if (cmp >= h) {
      cout << ans << endl;
      return 0;
    }
  }
  if (cmp < h) {
    while (cmp < h) {
      cmp += a[0];
      ans++;
    }
  }
  cout << ans << endl;
  return 0;
}
