#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
string s,a;
int	top;
int main(){
	cin>>a;
	int len=a.size();
	for(int i=0;i<=len;i++)
	{	
		s[top++]=a[i];
	}
	for(int i=0;i<=len;i++)
	{
		if(s[i]=='+')
		{
			s[i]=s[i]-'0';
			s[i]=(s[i-2]-'0')+(s[i-1]-'0');
		}
		else if(s[i]=='-')
		{
			s[i]=s[i]-'0';
			s[i]=(s[i-2]-'0')-(s[i-1]-'0');
		}
		else if(s[i]=='*')
		{
			s[i]=s[i]-'0';
			s[i]=(s[i-2]-'0')*(s[i-1]-'0');
		}
		else if(s[i]=='/')
		{
			s[i]=s[i]-'0';
			s[i]=(s[i-2]-'0')/(s[i-1]-'0');
		}
	//	else 
	//	{
	//		s[i]=s[i]-'0';
	//	}
	}
	cout<<s[top];

    return 0;
}