#include<iostream>
using namespace std;
char s[100];

int p[100];
int top=1;


	cin>>s;
	for(int i=0;s[i]!='@';i++)
	{
		if(s[i]>='0'&&s[i]<='9')
		{
			p[top]=p[top]*10+(s[i]-'0');
		}
		if(s[i]=='.')
		{
			top++;
			p[top]=0;
		}
		if(s[i]=='+')
		{
			p[top-2]+=p[top-1];
			top--;
			p[top]=0;
		}
		if(s[i]=='-')
		{
			p[top-2]-=p[top-1];
			top--;
			p[top]=0;
		}
		if(s[i]=='*')
		{
			p[top-2]*=p[top-1];
			top--;
			p[top]=0;
		}
		if(s[i]=='/')
		{
			p[top-2]/=p[top-1];
			top--;
			p[top]=0;
		}
	}
	cout<<p[1];
	return 0;
}