#include <iostream>
#include <cstdio>
using namespace std;
const int N=1005;
int n,ls[N],rs[N],val[N],fa[N];
int dfs(int x){
	if(x<=n)return val[x];
	int a=dfs(ls[x]),b=dfs(rs[x]);
	if(val[x]=='+')return a+b;
	if(val[x]=='-')return a-b;
	if(val[x]=='*')return a*b;
	if(val[x]=='/')return a/b;
	return 0;
}
int main(){
	freopen("expr_tree.in","r",stdin);
	freopen("expr_tree.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		scanf("%d",val+i);
	}
	for(int i=n+1;i<=n*2-1;i++){
		char str[5];
		scanf("%s %d %d",str,ls+i,rs+i);
		val[i]=str[0],fa[ls[i]]=1,fa[rs[i]]=1;
	}
	for(int i=1;i<=n*2-1;i++){
		if(!fa[i]){
			printf("%d\n",dfs(i));
			return 0;
		}
	} 
	return 0;
}