#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6;
int a[maxn], b[maxn];
int cmp(int a, int b) { return a > b; }
int main() {
  int n, m, i, j, maxa = 0, cnt = 0, sum = 0;
  cin >> n >> m;
  for (i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (maxa < a[i]) {
      maxa = a[i];
    }
  }
  sort(b, b + n, cmp);
  for (i = 0; b[i] > maxa && i < n; i++) {
    cnt++;
    sum += b[i];
  }
  if (sum >= m)
    cout << cnt << endl;
  else {
    while (sum < m) {
      cnt++;
      sum += maxa;
    }
    cout << cnt << endl;
  }
}
