#include<stdio.h>
#include<string.h>
#include<ctype.h>
#define max 100
char stack[max];
int top = -1;
int isOperator(char c){
    return(c =='+' || c=='-' || c=='*' || c=='/'); 
}
int precedence(char ch){
    if(ch=='+' || ch =='-')return 1;
    if(ch=='*' || ch =='/')return 2;
    return 0;
}
int main(){
    char infix[max],postfix[max]="";
    char op[max];
    int optop=-1;
    scanf("%s", infix);
    for(int i = 0;infix[i] != '\0';i++){
        char ch=infix[i];
        if(isalnum(ch)){
            char temp[2];
            temp[0]=ch;
            temp[1]='\0';
            strcat(postfix,temp);
        }
        else if(ch=='('){
            op[++optop]=ch;
        
    }
    else if(ch==')'){
        while(!optop != -1) && op[optop] !='('){
          char temp[2];
          temp[0]=op[optop--];
          temp[1]='\0';
          strcat(postfix,temp);
    }
    if(optop==-1){
        printf("Invalid input");
        return 0;
    }
    optop--;
}
else if(isOperator(ch)){
     while(optop != -1) && precedence(op[optop]) >= precedence(ch)){
          char temp[2];
          temp[0]=op[optop--];
          temp[1]='\0';
          strcat(postfix,temp);
    }
    op[++optop]=ch;
    
}
else{
    printf("Invalid input");
    return 0;
    }
}
while(optop != -1){
    if(op[optop--] == '('){
        printf("Invalid input");
        return 0;
    }
    char temp[2];
    temp[0] = op[optop--];
    temp[1]='\0';
    strcat(postfix,temp);
}
printf("%s", postfix);
return 0;
}