#include <bits/stdc++.h>
using namespace std;
bool compare_by_a(pair<int, int> a, pair<int, int> b) {
  if (a.first != b.first) {
    return a.first < b.first;
  } else {
    return a.second < b.second;
  }
}
int main() {
  long long n, h;
  cin >> n >> h;
  long long max = -114514;
  queue<long long> q;
  vector<long long> v(n);
  for (int i = 0; i < n; i++) {
    long long nage, huri;
    cin >> huri >> nage;
    if (max < huri) {
      max = huri;
    }
    v[i] = nage;
  }
  for (int i = 0; i < n; i++) {
    if (v[i] > max) {
      q.push(v[i]);
    }
  }
  long long ans = 0;
  while (h > 0) {
    if (!q.empty()) {
      h -= q.front();
      ans++;
      q.pop();
    } else {
      h -= max;
      ans++;
    }
  }
  cout << ans << endl;
}
