#include <bits/stdc++.h>
using namespace std;
const int inf = 2e9;
const long long INF = 4e17;
const int mod = 1e9 + 7;
const double eps = 1e-9;
long long b[100010];
int main() {
  long long n, h, last = 0, power = -inf, rel;
  scanf("%lld %lld", &n, &h);
  for (int i = 0; i < n; i++) {
    long long x;
    scanf("%lld %lld", &x, &b[i]);
    if (x > power) {
      power = x;
      rel = b[i];
    }
  }
  long long sum = 0;
  long long cnt = 0;
  for (int i = 0; i < n; i++) {
    if (b[i] >= power) sum += b[i], cnt++;
  }
  h -= sum;
  long long asdf = ceil((double)h / power);
  printf("%lld\n", cnt + asdf);
  return 0;
}
