#include <bits/stdc++.h>
int main() {
  long long int n;
  long long int h;
  int a[1000000000];
  int b[1000000000];
  scanf("%lld %lld", &n, &h);
  for (int i = 0; i < n; i++) {
    scanf("%d %d", &a[i], &b[i]);
  }
  long long int count = 0;
  long long int max = 1000000001;
  for (long long int i = 0; i < n; i++) {
    long long int tmp = 0;
    for (long long int j = 0; j < n; j++) {
      if (max > b[i])
        if (b[i] > tmp) {
          tmp = b[i];
        }
    }
    max = tmp;
    h -= tmp;
    count++;
    if (h <= 0) goto FINISH;
  }
  max = 0;
  for (long long int i = 0; i < n; i++) {
    if (max < a[i]) max = a[i];
  }
  while (h <= 0) {
    h -= max;
    count++;
  }
FINISH:
  printf("%lld\n", count);
}
