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

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] == '-'){
			a = pop();
			b = pop();
			push(a -b);
		}else if(s[0] == '*'){
			a = pop();
			b = 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;
}