#include <bits/stdc++.h>
using namespace std;
long long int t, n;
int main() {
  cin >> n >> t;
  long long int k = 0;
  long long int a, b;
  long long int res1 = 1;
  long long int res;
  cin >> a >> b;
  long long int m = (t - a) / b;
  if (a >= t)
    res = a;
  else if (m * b + a == t)
    res = t;
  else
    res = (m + 1) * b + a;
  for (int i = 1; i < n; i++) {
    cin >> a >> b;
    m = (t - a) / b;
    if (a >= t) {
      if (a < res) {
        res = a;
        res1 = i + 1;
      }
    } else if (m * b + a == t) {
      res = t;
      res1 = i + 1;
    } else if ((m + 1) * b + a < res) {
      res = (m + 1) * b + a;
      res1 = i + 1;
    }
  }
  cout << res1;
}
