#include <bits/stdc++.h>
using namespace std;
int atk[100005], datk[100005];
int main() {
  int N, H, cnt = 0, maks = 0;
  cin >> N >> H;
  for (int i = 1; i <= N; i++) {
    cin >> atk[i] >> datk[i];
    if (atk[i] > maks) {
      maks = atk[i];
    }
  }
  for (int i = 1; i <= N; i++) {
    if (datk[i] > maks) {
      cnt++;
      H -= datk[i];
    }
  }
  if (H % maks == 0 || H < 0) {
    cout << cnt + H / maks;
  } else {
    cout << cnt + H / maks + 1;
  }
}
