#include<bits/stdc++.h>
using namespace std;
stack<char>stk; 
int main()
{
	string s;
	int i=0,sum=0;
	getline(cin,s);
	while(s[i]!='@')
	{
		while(s[i]>='0'&&s[i]<='9')
		{
			sum=sum*10+s[i]-'0';
	   		i++;
		}
		if(s[i]==' ')
		{
			stk.push(sum);
			sum=0;
			i++;
		}
		else
		{
			int a,b;
			a=stk.top();
			stk.pop();
			b=stk.top();
			stk.pop();		
			switch(s[i])
			{
				case '+': stk.push(a+b);break;
		   	    case '-': stk.push(b-a);break;
				case '*': stk.push(a*b);break;
				case '/': stk.push(b/a);break;		
			}
			i++;
		}
	cout<<stk.top();
	return 0;
	}
}
/**/