#include <cstdio>
#include <algorithm>
using namespace std;
int N, H, amax = 0, b[100001], ans;
int main() {
  scanf("%d %d", &N, &H);
  for(int i = 1, a; i <= N; ++i) {
    scanf("%d %d", &a, &b[i]);
    amax = max(amax, a);
  }
  sort(b+1, b+N+1);
  for(int i = N; i > 0; --i) {
    if(b[i] <= amax) break;
    H -= b[i]; ++ans;
    if(H <= 0) break;
  }
  if(H > 0) ans += (H+amax-1)/amax;
  printf("%d\n", ans);
}