#include<stdio.h>
#include<stdlib.h>
#include<string.h>
// #include <bits/stdc++.h>
// using namespace std;


int top, S[1000];

void push(int x){
	S[++top] = x;
}
int pop(){
	top--;
	return S[top+1];
}

int main() {
	int a, b;
	top = 0;
	char s[100];
	while( scanf("%s", s) != EOF) {
		if( s[0] == '+') {
			a = pop();
			b = pop();
			push(a + b);
		} else if (s[0] == '-') {
			b = pop();
			a = pop();
			push(a - b);
		}else if (s[0] == '*') {
			a = pop();
			b = pop();
			push(a * b);
		} else {
			push(atoi(s));
		}
	}

	printf("%d¥n", pop());
	return 0;
}

