#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, m;
  cin >> n >> m;
  vector<pair<long long, long long> > v;
  vector<long long> dmg;
  long long maxdmg = 0, garbo = 0;
  for (long long i = 0; i < n; ++i) {
    long long tmp, tmp1;
    cin >> tmp >> tmp1;
    v.push_back(make_pair(tmp, tmp1));
    dmg.push_back(tmp1);
    if (tmp > maxdmg) maxdmg = tmp;
  }
  long long i = 0;
  for (auto x : dmg) {
    if (x > maxdmg) garbo += x, ++i;
  }
  while (garbo < m) {
    garbo += maxdmg;
    i++;
  }
  cout << i;
  return 0;
}
