#include <bits/stdc++.h>
const int MGN = 8;
const int ARY_SZ_MAX = 10000000;
using namespace std;
using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vd = vector<double>;
using vs = vector<string>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using psi = pair<string, int>;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int N, H;
  cin >> N >> H;
  vi A(N), B(N);
  for (int i = int(0); i < int(N); ++i) cin >> A[i] >> B[i];
  vector<pii> c;
  for (int i = int(0); i < int(N); ++i) c.push_back(pii(A[i], B[i]));
  sort(c.begin(), c.end());
  int a = c[N - 1].first;
  int h = H;
  int cnt = 0;
  for (int i = int(0); i < int(N); ++i) {
    if (a < c[i].second) {
      h -= c[i].second;
      cnt++;
    }
  }
  cnt += (h + a - 1) / a;
  int ans = cnt;
  cout << ans << endl;
  return 0;
}
