AIPS-Vezbi za prv kolokvium-Opseg

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Range {

    static long proveri(long N, long A, long B) {
        // Vasiot kod tuka
      long x1=((-1)*200+(long)Math.sqrt(200*200+4*N))/2;
      long x2=((-1)*200+(long)Math.sqrt(200*200+4*N))/2;
      if(x1>=A&&x1<=B)
          return x1;
      else if(x2>=A&&x2<=B)
        return x2;
      else
          return -1;

    }

    public static void main(String[] args) throws Exception {
        int i,j,k;

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        long N = Long.parseLong(br.readLine());

        StringTokenizer st = new StringTokenizer(br.readLine());
        long A = Long.parseLong(st.nextToken());
        long B = Long.parseLong(st.nextToken());

        long res = proveri(N, A, B);
        System.out.println(res);

        br.close();

    }

}