#include <bits/stdc++.h>
using namespace std;
int N;
int H;
int b[10000];
int main(void) {
  scanf("%d %d\n", &N, &H);
  int a;
  int max_a = 0;
  for (int i = 0; i < N; i++) {
    scanf("%d %d\n", &a, &b[i]);
    max_a = max(max_a, a);
  }
  int turn = 0;
  for (int i = 0; i < N; i++) {
    if (max_a > b[i]) continue;
    H -= b[i];
    turn++;
    if (H <= 0) {
      cout << turn << "\n";
      return 0;
    }
  }
  cout << turn + ((H - 1) / max_a) + 1 << "\n";
  return 0;
}
