#include <bits/stdc++.h>
using namespace std;
const int N = 100010, M = 2 * N;
int n, h;
int a[N], b[N];
priority_queue<int, vector<int>, greater<int>> heap;
int main() {
  scanf("%d%d", &n, &h);
  int maxa = 0, res = 0;
  long long sum = 0;
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &a[i], &b[i]);
    maxa = max(maxa, a[i]);
  }
  for (int i = 1; i <= n; i++)
    if (b[i] > maxa) {
      sum += b[i];
      heap.push(b[i]);
      res++;
      if (sum >= h) {
        printf("%d\n", res);
        return 0;
      }
    }
  int t = (h - sum + maxa - 1) / maxa;
  sum += t * maxa;
  res += t;
  while (heap.size() && sum - heap.top() >= h) {
    sum -= heap.top();
    heap.pop();
    res--;
  }
  printf("%d\n", res);
  return 0;
}
