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

void push(int );
void calc(char );

int top=1;
int s[100];

int main(){

  char num[4];
  int i,tmp,flag=0;
  
  while(1){
    if(scanf("%s",num) == EOF)break;
    
    flag =0;
    for(i=0;i<strlen(num);i++){//数字判定
      if(num[i]< '0'|| '9'< num[i])flag=1;
    }
    
    if(flag == 0)push(atoi(num));//数字
  
    if(num[0] == '+'|| num[0]== '-'|| num[0] == '*') calc(num[0]);//演算子
  
  }
  printf("%d\n",s[1]);
  
  return 0;
}

void push(int x){
  s[top]=x;
  // printf("入った数字%d\n",s[top]);
  top++;
}

void calc(char ope){
 top--;
  if(ope=='+')s[top-1] = s[top-1]+s[top];
  if(ope=='-')s[top-1] = s[top-1]-s[top];
  if(ope=='*')s[top-1] = s[top-1]*s[top];

  // printf("")

 
}

