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

int iscalcu(char c) {
	return ((c=='+')||(c=='-')||(c=='*')||(c=='/'));
}

int main() {
	int num[1000] = {0}, top_loc = -1;
	int temp = 0;
	char s[1000];
	memset(s, 0, 1000);
	int i, j;
	fgets(s, 1000, stdin);
	int l = strlen(s);
	while ( s[l] == '\r' || s[l] == '\n') s[l--] = '\0';
	for(i = 0; s[i] != '@'; i++) {
		if(isdigit(s[i])) {
			temp = 0;
			while (s[i] != '.') {
				temp = temp*10 + s[i] - '0';
				i++;
			}
			num[++top_loc] = temp;
		}
		if(iscalcu(s[i])) {
			if(s[i] == '+') {
				num[top_loc-1] = num[top_loc-1] + num[top_loc--];
			}
			if(s[i] == '-') {
				num[top_loc-1] = num[top_loc-1]-num[top_loc--];
			}
			if(s[i] == '*') {
				num[top_loc-1]=num[top_loc-1]*num[top_loc--];
			}
			if(s[i] == '/') {
				num[top_loc-1]=num[top_loc-1]/num[top_loc--];
			}
		}
	}
	printf("%d\n",num[0]);

	return 0;
}