我们发现当 $x>\lfloor\frac n2\rfloor$ 时你找不到两个合法的 $y,z$。当 $x=\lfloor\frac n2\rfloor$ 可以找到 $y=\lfloor\frac n2\rfloor,z=2y$。所以这个 $x$ 就是答案。

你以为这就满分了吗？注意到可能有多个 $y,z$ 是 $x$ 的倍数。当 $n$ 是偶数显然恰有两个 $y,z$，当 $n$ 为奇数考虑 $n\ge3\lfloor\frac n2\rfloor=\frac{3(n-1)}{2}$，$n\le 3$。发现 $n=3$ 时实际有 $y=2,z=3$。特判即可。

下面给出 spj 实现：

int n,s;
n=inf.readInt();s=inf.readInt();
int a=n/2,b=n/2,c=n/2*2;
if(n==3)b=2,c=3;
int A=ouf.readInt(),B=ouf.readInt(),C=ouf.readInt();
if(s<=1){
	if(A==0&&B==0&&C==0){
		if(s==1)quitp(0.520,"Sadly, you lost the game.");
		else quitp(0.8,"A draw! You're strong enough to be an administrator, but cyx may not allow it.");
	}
}
if(B<1||C<1||B>=C||C>n)quitf(_wa,"Ridiculous game!");
if(A==a&&B==b&&C==c)quitf(_ok,"You have won, and you have perfectly won");
if(A==a)quitp(0.9,"You are close to a perfect win, but still a little bit further! However, who told you to win the game? Do you think he'll really give out his girlfriend?");
if(s>A)quitp(0.520,"Sadly, you lost the game.");
if(s==A)quitp(0.8,"A draw! You're strong enough to be an administrator, but cyx may not allow it.");
if(s<A)quitp(0.1314,"Who told you to win the game? Do you think he'll really give out his girlfriend?");