#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<pair<long long, long long> > v;
  for (int i = 0; i < n; i++) {
    long long a, b;
    cin >> a >> b;
    v.push_back(pair<long long, long long>(a, b));
  }
  sort(v.begin(), v.end(), greater<pair<long long, long long> >());
  long long ans = 0, val = v[0].first;
  for (int i = 0; i < n; i++) {
    if (v[i].second < val) continue;
    hp -= v[i].second;
    ans++;
    if (hp <= 0) break;
  }
  ans += (hp + val - 1) / val;
  cout << ans << endl;
  return 0;
}
