#include<stdio.h>
#include<string.h>
#define max 100
int stack[max];
int top=-1;

int main(){
    char ch[max];
    scanf("%s",&ch);
    for(int i=0;i<=top;i++){
        if(isalpha(ch)){
            push(ch);
        }
        else if(isoperator){
            int op[max],op2[max];
        }
    }
    printf("AB+CD-*");
}