#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1, 1, -1, 1, -1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
long long gcd(long long a, long long b) { return !b ? a : gcd(b, a % b); }
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
void PLAY() {
  cout << fixed << setprecision(10);
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int main() {
  int n, h;
  cin >> n >> h;
  vector<pair<long long, int>> v;
  int x;
  for (int i = 0; i < n; i++) {
    cin >> x;
    v.push_back({x, 1});
    cin >> x;
    v.push_back({x, 0});
  }
  sort(v.rbegin(), v.rend());
  long long res = 0;
  for (int i = 0; i < (int)v.size(); i++) {
    if (v[i].second == 1) {
      res += h / v[i].first;
      h %= v[i].first;
      if (h > 0) res++;
      break;
    } else {
      res++;
      h -= v[i].first;
    }
  }
  cout << res << endl;
  return 0;
}
