백준 1300

package baekjoon.이분탐색;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class Main1300 {

   static int N, K;

   public static void main(String[] args) throws Exception {
      input();
      go();
   }

   private static void go() {
      long L = 1, R = (long)N * N, ans = 0;
      while (L <= R) {
         long mid = (L + R) / 2;
         if (determination(mid)) {
            ans = mid;
            R = mid - 1;
         } else {
            L = mid + 1;
         }
      }
      System.out.println(ans);
   }

   private static boolean determination(long mid) {
      long cnt = 0;
      for (int i = 1; i <= N; i++) {
         cnt += Math.min(N, mid / i);
      }

      return cnt >= K;
   }

   private static void input() throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      N = Integer.parseInt(br.readLine());
      K = Integer.parseInt(br.readLine());
   }
}