#include <bits/stdc++.h>
using namespace std;
int maxa;
int B[100000];
int main() {
  int N;
  long long H;
  int maxa = 0;
  long long cnt = 0;
  int bpos = 0;
  cin >> N;
  scanf("%ld", &H);
  for (int i = 0; i < N; ++i) {
    int tmpa;
    scanf("%d", &tmpa);
    scanf("%d", &B[i]);
    if (maxa < tmpa) maxa = tmpa;
  }
  sort(B, B + N, greater<int>());
  while (bpos < N && maxa < B[bpos]) {
    H -= B[bpos];
    ++cnt;
    ++bpos;
  }
  cnt += (H / maxa);
  if (H % maxa != 0) ++cnt;
  cout << cnt << "\n";
}
