Calculate Perfect Square using Java

// perfect square

import java.io.*;

class ssvps
 {
   public static void main(String arg[]) throws IOException
   {
    String s1;

    int m,n;

    int p;

    DataInputStream dr = new DataInputStream(System.in);

    System.out.print("\nEnter the Number : ");

    s1 = dr.readLine();

    n = Integer.parseInt(s1);

      p=(int)sqrt(n);

      m = p;

      if(p == m)

       System.out.println("\nit is Perfect Square"+n);

    else

       System.out.println("\nit is Not Perfect Square"+n);

  }
 }