#include<bits/stdc++.h>
using namespace std;
stack<int>n;
int s=0,x,y;
int main(){
	char ch;
	while((ch=getchar())!='@'){
		if(ch>='0'&& ch<='9')
		s=s*10+ch-'0';
	else if(ch=='.')
		n.push(s),s=0;
	else{
		x=n.top();n.pop();y=n.top();n.pop();
		switch(ch){
			case'+':n.push(x+y);break;
			case'-':n.push(y-x);break;
			case'*':n.push(x*y);break;
			case'/':n.push(y/x);break;
		}
	}
		}
		cout<<n.top();
		return 0;
}