#include<bits/stdc++.h>
#define N 100005
#define ll long long
using namespace std;
ll n;
stack<ll> c;
ll read(){
	char x;
	ll k=0;
	while((x=getchar())!='.'){
		if(x>'9'||x<'0')return x;
		k=k*10+x-'0';
	}
	return k;
}
int main() {
	ll x,y;
	while((n=read())!='@'){
		switch(n){
			case '+':x=c.top();c.pop();y=c.top();c.pop();c.push(y+x);break;
			case '-':x=c.top();c.pop();y=c.top();c.pop();c.push(y-x);break;
			case '*':x=c.top();c.pop();y=c.top();c.pop();c.push(y*x);break;
			case '/':x=c.top();c.pop();y=c.top();c.pop();c.push(y/x);break;
			default:{
			c.push(n);break;
			}
		}
	}
	cout<<c.top();
	return 0;
}

第五个点re