后缀表达式运算

//"6 9 + 5 3 * - 8 -"
#include <bits/stdc++.h>
using namespace std;
int n,i = 0,a[100];
char a1;
int main(){
	cin>>n;
	while(n--){
		cin>>a1;
		if(a1>='1' && a1<='9'){
			a[++i] = a1-'0';
		}else{
			int x,y,num = 0;
			y = a[i--];
			x = a[i--];
			if(a1=='+'){
				num = x+y;
			}else if(a1=='-'){
				num = x-y;
			}else if(a1=='/'){
				num = x/y;
			}else{
				num = x*y;
			}
			a[++i] = num;
		}
	}
	cout<<a[i];
	return 0;
}