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

typedef struct{
  int top;
  int items[251];
}STACK;

void push(int x, STACK *ps){
  if(ps->top == 250){
    printf("Error: stack overflow");
    exit(EXIT_FAILURE);
    }else
      ps->items[++(ps->top)] = x;
 return;
}

int pop(STACK *ps){
/*  if(empty(ps)){
    printf("Error: stack underflow");
    exit(EXIT_FAILURE);
    }else */
return(ps->items[(ps->top)--]);
}

int main(void){

int pole [30];
char string [250];
STACK stack;
stack.top = -1;
int cislo;
int operacia;
int vysledok;

while(scanf("%s",string) != EOF){
    if (strcmp("+",string)){
      operacia = pop(&stack) + pop(&stack);
      push(operacia,&stack);}else
    if (strcmp("-",string)){
      operacia = pop(&stack) + pop(&stack);
      push(operacia,&stack);}else
    if (strcmp("*",string)){
      operacia = pop(&stack) + pop(&stack);
      push(operacia,&stack);}else
    if (strcmp("/",string)){
      operacia = pop(&stack) + pop(&stack);
      push(operacia,&stack);}else{
        cislo = atoi(string);
        push(cislo,&stack);
        }
}
vysledok = pop(&stack);

printf("%d",vysledok);

return 0;
}