#include<iostream>

#include<cstring>

#include<cstdio>

using namespace std;

typedef long long LL;

LL a[];

LL dp[][];

LL Com(LL n, LL m){

    if(!m || n == m) return ;

    LL & res = dp[n][m];

    if(res != -) return res;

    return res = Com(n-, m) + Com(n-, m-);

}

void Init(){

    a[] = a[] = ;

    a[] = ;

    for(int i = ; i <= ; i++)

        a[i] = (i - )*(a[i-] + a[i-]);

}

int main(){

    LL n;

    Init();

    while(scanf("%I64d", &n) ==  && n){

        LL m = n/;

        LL sum = ;

        memset(dp, -, sizeof(dp));

        for(int i = ; i <= m; i++)

            sum += Com(n, i)*a[i];

        printf("%I64d\n", sum);

    }

    return ;

}