鸡兔筒笼,砍脚法
Scanner in=new Scanner(System.in);
int a=in.nextInt();
int b=in.nextInt();
int c=0;
if (b%2==0&&a<=(b/2)){
c=a*2;
b-=c;
b/=2;
a-=b;
System.out.println(a+" "+b);
}
else {
System.out.println("No answer");
}
}