#include <bits/stdc++.h>
using namespace std;
long long Y[100005];
long long a, h;
long long getCount(long long sm) { return ceil((0LL + h - sm) / (double)a); }
int main() {
  int n;
  long long x;
  long long bsum = 0, ans;
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    scanf("%lld %lld", &x, &Y[i]);
    a = max(a, x);
  }
  sort(Y, Y + n);
  bsum = 0;
  ans = getCount(bsum);
  for (int i = n - 1; i >= 0; i--) {
    bsum += Y[i];
    ans = min(ans, getCount(bsum) + (n - i));
  }
  cout << ans;
  return 0;
}
