#include<stdio.h>
#include<string.h>
#define max 25
int top=-1;
char stack[max][max];

char push(char *ch){
    return strcpy(stack[++top],ch);
}
void pop{
    return stack[top--];
}

char isoperand(char *ch){
    return ch=='('ch=='+'||ch=='-'||ch=='*'||ch=='/'||ch==")";
}

char isoperator(char ch){
    return isalnum(ch)||ch=='+'||ch=='-'||ch=='*'||ch=='/';
}

void fun(char *str){
    top=-1;
    int len=strlen(str),i;
    
    for(int i=len-1;i<=0;i++){
        char ch[max]=str[i];
           if(!isalnum(ch)){
            char temp[2];
            temp[0]=ch;
            temp[1]='\0';
            push(temp);
        }
        if(!isoperator(ch)){
            char op1[max],op2[max],final[max];
            strcpy(op1,push());
            strcpy
        }
        
    
    }
    printf("%c ",top);
}


int main(){
    char str[max];
    scanf("%[^\n]c",str);
    fun(str);
}