#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5, M = 1e6 + 6, OO = 0x3f3f3f3f;
long long OOL = 0x3f3f3f3f3f3f3f3f;
long long n, h;
bool cmp(pair<int, int> x, pair<int, int> y) { return x.second < y.second; }
pair<long long, long long> arr[N];
int mem[1000][1000];
int dp(long long hp, int idx, int total) {
  if (hp <= 0) {
    return total;
  }
  if (idx == n)
    return OO;
  else {
    long long op1 = dp(hp - arr[idx].first, idx, total + 1);
    long long op2 = dp(hp - arr[idx].second, idx + 1, total + 1);
    long long op3 = dp(hp, idx + 1, total);
    return mem[hp][idx] = min(op1, min(op2, op3));
  }
}
int main() {
  scanf("%lld %lld", &n, &h);
  for (int i = 0; i < n; i++) scanf("%lld %lld", &arr[i].first, &arr[i].second);
  sort(arr, arr + n);
  int tmp = h;
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    if (arr[i].second >= arr[n - 1].first) {
      tmp -= arr[i].second;
      ans++;
    }
    if (tmp <= 0) break;
  }
  if (tmp > 0) {
    ans += (tmp + arr[n - 1].first - 1) / arr[n - 1].first;
  }
  cout << ans << endl;
  return 0;
}
