#include <bits/stdc++.h>
using namespace std;
constexpr double PI = 3.1415926535897932;
constexpr double EPS = 1e-9;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, h;
  cin >> n >> h;
  int maxe = 0;
  vector<int> b(n);
  for (int i = 0; i < n; ++i) {
    int a;
    cin >> a >> b[i];
    maxe = max(maxe, a);
  }
  long long ans = 0;
  for (int i = 0; i < n; ++i) {
    if (b[i] <= maxe) continue;
    h -= b[i];
    ++ans;
    if (h <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  ans += ceil((double)h / maxe);
  cout << ans << endl;
}
