#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 30;
const int MOD = 1e9 + 7;
const int dy[] = {1, 0, -1, 0};
const int dx[] = {0, 1, 0, -1};
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  long long hp;
  cin >> hp;
  vector<long long> a(n), b(n);
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  sort(a.begin(), a.end(), greater<long long>());
  sort(b.begin(), b.end(), greater<long long>());
  long long ans = 0, val = a[0];
  for (int i = 0; i < n; i++) {
    if (b[i] <= val || hp <= 0) break;
    hp -= b[i];
    ans++;
  }
  ans += (hp + val - 1) / val;
  cout << ans << endl;
  return 0;
}
