#include <bits/stdc++.h>
const int N = 1e9;
const int mod = (int)1e9 + 7;
const int INF = 0x3f3f3f3f;
const double PI = acos(-1.0);
const int maxn = 1e5 + 5;
using namespace std;
int second[maxn];
bool cmp(int a, int b) { return a > b; }
int gcd(int a, int b) { return (b == 0) ? a : gcd(b, a % b); }
int main() {
  int N, H, mxn, b, a, ans, temp;
  mxn = temp = 0;
  cin >> N >> H;
  for (int i = 0; i < N; i++) {
    cin >> a >> second[i];
    mxn = max(mxn, a);
  }
  for (int i = 0; i < N; i++) {
    if (second[i] > mxn) {
      H -= second[i];
      temp++;
    }
  }
  if (H <= 0)
    ans = temp;
  else {
    ans = temp + H / mxn;
    if (H / mxn * mxn < H) ans++;
  }
  cout << ans;
  return 0;
}
