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

int main(){
    int x;
    char s[200];
    signed long long stack[200];
    int esp=0;

    while( scanf("%s",s) != EOF){
        if(s[0] == '+'){
            esp--;
            stack[esp-1] += stack[esp];
        } else if(s[0] == '-'){
            esp--;
            stack[esp-1] -= stack[esp];
        } else if(s[0] == '*'){
            esp--;
            stack[esp-1] *= stack[esp];
        } else {
            x = atoi(s);
            stack[esp] = x;
            esp++;
        }
    }

    printf("%lld\n", stack[0]);

    return 0;
}
