public static int jump(int startPoint, int distance){
        return startPoint + distance;
    }
    public static String checkRes(int x1, int v1, int x2, int v2){            
        if ((x2 > x1 && v2 >= v1) || (x1 > x2 && v1 >= v2)) { 
            return "NO";
        }
        if ((v1>10000) || (v2>10000)){
            return "NO";
        }
        int res1 = jump(x1, v1);
        int res2 = jump(x2, v2);
        
        if(res1 == res2){
            return "YES";
        }else{
            return checkRes(res1, v1, res2, v2);
        }
    }
    public static String kangaroo(int x1, int v1, int x2, int v2) {
       return checkRes(x1, v1, x2, v2);

    }

}