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

void push(char* ch){
    strcpy(stack[++top],str);
}
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){
    int len=strlen(str),i;
    
    for(i=len-1;i<=0;i--){
        char ch=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,pop());
            strcpy(op2,pop());
            strcpy(final,op1);
            strcat(final,op2);
            int l=strlen(final);
            final[l]=ch;
            final[l+1]='\0';
            push(final);
        }
        
    
    }
    printf("%s",stack[top]);
}


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

    
    getchar();
    fun(str);
}