#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_a) > (a)) ? (max_a) : (a));
  }
  int turn = 0;
  for (int i = 0; i < N; i++) {
    if (max_a < b[i]) {
      H -= b[i];
      turn++;
      if (H <= 0) {
        cout << turn << "\n";
        return 0;
      }
    }
  }
  cout << turn + ((H - 1) / max_a) + 1 << "\n";
  return 0;
}
