#include <bits/stdc++.h>
using namespace std;
static const long long MOD = 1e9 + 7;
static const long long MAX_L = (long long)1 << 62;
static const long long FACT_SIZE = 1000000;
long long a[100001] = {};
long long b[100001] = {};
int main() {
  long long n, h;
  cin >> n >> h;
  long long maxV = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    maxV = max(maxV, a[i]);
  }
  long long ans = 0;
  for (long long i = 0; i < n; i++) {
    if (maxV <= b[i]) {
      h -= b[i];
      ans++;
    }
  }
  if (h > 0) {
    if (h % maxV != 0) ans++;
    ans += (h / maxV);
  }
  cout << ans << endl;
  return 0;
}
