#include<iostream>
using namespace std;
struct nod{
	int lch,rch,val,par;
}tre[2049];
int n;
int f(int x){
	if(x<=n) return tre[x].val;
	else{
		if(tre[x].val==-1) return f(tre[x].lch)+f(tre[x].rch);
		else if(tre[x].val==-2) return f(tre[x].lch)-f(tre[x].rch);
		else if(tre[x].val==-3) return f(tre[x].lch)*f(tre[x].rch);
		else if(tre[x].val==-4) return f(tre[x].lch)/f(tre[x].rch);
	}
}
int main(){
	freopen("expr_tree.in","r",stdin);
	freopen("expr_tree.out","w",stdout);
	
	scanf("%d",&n);
	for(int i=1;i<=n;i++) cin>>tre[i].val;
	for(int i=n+1;i<=n*2-1;i++){
		char q;cin>>q;
		if(q=='+') tre[i].val=-1;
		else if(q=='-') tre[i].val=-2;
		else if(q=='*') tre[i].val=-3;
		else if(q=='/') tre[i].val=-4;
		cin>>tre[i].lch>>tre[i].rch;
		tre[tre[i].lch].par=i;
		tre[tre[i].rch].par=i;
	}
	int rt=1;
	while(tre[rt].par) rt=tre[rt].par;
	cout<<f(rt);
	
	fclose(stdin);
	fclose(stdout);
	return 0;
}