#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] == "-"){
   	  b = pop();
   	  a = pop();
   	  push(a - b);
   }else if(s[0] == "*"){
   	  a = pop();
   	  b = pop();
   	  push(a * b);
   }else{
   	  push(atoi(s));
   }
   print("%d\n",pop());
   return 0;
}