#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int top = 0, S[1000];

void push(int x){
	S[++top] = x;
}

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

int main(void){
	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 if(s[0] == '/'){
			b = pop();
			a = pop();
			push(a / b);
		} else {
			push(atoi(s));
		}
	}
	printf("%d\n", pop());
	
	return 0;
}
