#include<stdio.h>
const unsigned int ans[]={1,2,5,14,42,132,429,1430,4862,16796,58786,208012,742900,2674440,9694845,35357670,129644790,477638700};
int n;
int main()
{
	scanf("%d",&n);
	printf("%d",ans[n-1]);
	return 0;
}

为什么我这个平平无奇的大表程序被360、腾讯电脑管家等3个杀毒软件检测为Win32/Trojan.b7f ？？？(360还是上报过的