#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));                                                                                                                               
  }                                                                                                                                                   
  printf("%d\n",pop());                                                                                                                               
                                                                                                                                                      
  return 0;                                                                                                                                           
}                                                                                                                                                     

Measured memory_bytes: 2740