#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main(){
  int N;
  long long M, A, B, ans = 0, c = 0;
  cin >> N >> M;
  map<long long, int> m;
  rep(i, N){
    cin >> A >> B;
    m[(M-A)/B+1]++;
  }
  for(auto x: m){
    c += x.second;
    ans = max(ans, (c+x.first-1)/x.first);
  }
  cout << ans << endl;
}