#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T &a, const T b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
const int inf = 1e9 + 10, mod = 1e9 + 7;
const long long llinf = 1e18;
int main() {
  int n, h, a, b;
  int count = 0;
  cin >> n >> h;
  vector<int> A(n), B(n);
  for (int i = 0; i < n; i++) {
    cin >> a >> b;
    A[i] = a;
    B[i] = b;
  }
  int MA = *max_element((A).begin(), (A).end());
  int i = 0;
  while (i < n && B[i] >= MA && h > 0) {
    count++;
    h -= B[i];
    i++;
  }
  count += (h - 1 + MA) / MA;
  cout << count << endl;
}
