#include <bits/stdc++.h>
using namespace std;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  int N, H;
  cin >> N >> H;
  int a[100005] = {};
  int b[100005] = {};
  int ma = 0;
  int ans = 0;
  for (int i = 1; i <= N; i++) {
    cin >> a[i] >> b[i];
    ma = max(ma, a[i]);
  }
  for (int i = N; i >= 1 && H > 0; i--) {
    if (b[i] > ma) {
      H -= b[i];
      ans++;
    }
  }
  ans += (H / ma);
  if (H % ma > 0) ans++;
  cout << (ans) << "\n";
  return 0;
}
