#include <bits/stdc++.h>
using namespace std;
const int INF = 1001001000;
const int mINF = -1001001000;
const long long LINF = 1010010010010010000;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
int n, h;
vector<long long> a(110000), b(110000);
int main() {
  cin >> n >> h;
  for (int i = 0; i < (n); ++i) cin >> a[i] >> b[i];
  long long mx = 0;
  int idx = -1;
  for (int i = 0; i < (n); ++i) {
    if (chmax(mx, a[i])) idx = i;
  }
  vector<long long> thr;
  for (int i = 0; i < (n); ++i) {
    if (b[i] > mx) thr.push_back(i);
  }
  long long sum = 0;
  for (int i = 0; i < ((int)thr.size()); ++i) {
    sum += b[thr[i]];
    if (sum >= h) {
      cout << i + 1 << endl;
      return 0;
    }
  }
  long long cnt = (int)thr.size();
  sum -= b[idx];
  cnt--;
  long long need = h - sum;
  cnt += (need - b[idx] + mx - 1) / mx;
  cout << cnt + 1 << endl;
  return 0;
}
