#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18;
const long long mod = 1e9 + 7;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n, h, a, x;
  cin >> n >> h;
  long long b[n + 1];
  for (long long i = (1); i <= (n); i++) {
    cin >> x >> b[i];
    a = max(a, x);
  }
  sort(b + 1, b + n + 1, greater<long long>());
  long long cnt = 0, sum = 0;
  for (long long i = (1); i <= (n); i++) {
    if (sum >= h) {
      cout << cnt;
      return 0;
    }
    if (b[i] < a) break;
    sum += b[i];
    cnt++;
  }
  if (sum >= h) {
    cout << cnt;
    return 0;
  }
  long long c = (h - sum) / a;
  if ((h - sum) % a) c++;
  cout << cnt + c;
}
