#include<cstdio>
typedef long long ll;
ll n,a[105],dp[105][25];
int main(){
    freopen(".10.in","r",stdin);
    freopen(".10.out","w",stdout);
	scanf("%lld",&n);
	for(int i = 1;i<=n;i++){
		scanf("%lld",&a[i]);
	}
	dp[1][a[1]] = 1;
	for(int i = 1;i<n;i++){
		for(int j = 0;j<=20;j++){
			if(j-a[i]>=0){
				dp[i][j] += dp[i-1][j-a[i]];
			}
			if(j+a[i]<=20){
				dp[i][j] += dp[i-1][j+a[i]];
			}
		}
	}
	printf("%lld",dp[n-1][a[n]]);
}