#include <bits/stdc++.h>
using namespace std;
int main(){
	stack<int>a;
	while(1+1==2){
		char n;
		int x,y;
		n=getchar();
		if(n=='.') continue;
		if(n=='@') break;
		if(n>='0'&&n<='9') a.push((int)(n-'0'));
		else{
			y=a.top();a.pop();x=a.top();a.pop();
			if(n=='-') a.push(x-y);
			if(n=='+') a.push(x+y);
			if(n=='*') a.push(x*y);
			if(n=='/') a.push(x/y);
			cout<<a.top();
		}
	}
	cout<<a.top();
	return 0;
}

感谢dalao们qwq