Java program for a game of dice is to be simulated for two players, each player gets a chance to throw his dice

A game of dice is to be simulated for two players, each player gets a chance to throw his dice, and the value is added to his points, this process continues alternately until for the player whose added points equals to 20 and is declared the winner. Write a program to simulate this process using the random( ) function.

import java.util.*;
class Game
{
	public static void main(String arr[])
	{
		int i,r1,r2,s1=0,s2=0;
		for(i=1;s1<20 && s2<20;i++)
		{
		r1=1+(int)(Math.random()*20);
		s1+=r1;
		if(s1<20)
		{
		r2=1+(int)(Math.random()*20);
		s2+=r2;
		}
		}
		if(s1>s2)
		System.out.println("Winner is player 1");
		else
		System.out.println("Winner is player 2");
	}
}