#include <iostream> //((a+b)*((-d)+(-e)))
#include <fstream>
#include <string>

using namespace std;


int fun(string &str)
{

    while(str.size())
    {
        cout<<str<<endl;

        if(str[0]=='(')
        {
            str=str.substr(1,str.size()-1);
            int k=fun(str);
            str=str.substr(k,str.size()-k);
            if(str[0]==')')
                continue;
            if(str[0]=='\0')
                return 0;
            if((str[0]=='-'||str[0]=='*'||str[0]=='+')&&((str[1]>=97&&str[1]<=122)||str[1]=='('))
            {
                str=str.substr(2,str.size()-2);
                continue;
            }

            if(str[0]!='*'&&str[0]!='+'&&str[0]!='-')
            {


                cout<<"Error1"<<endl;
                exit(0);
            }

        }
        else
        {

            if(str[0]==')')
            {
                if(str[1]>=97&&str[1])
                {
                    cout<<"Error2"<<endl;
                    exit(0);
                }
/*
                if(str[1]!=')'&&(str.size()-1))
                    str=str.substr(1,str.size()-1);
                    */
                str=str.substr(1,str.size()-1);
                if((str[0]=='-'||str[0]=='*'||str[0]=='+')&&((str[1]>=97&&str[1]<=122)||str[1]=='('))
                {
                    str=str.substr(2,str.size()-2);
                    continue;
                }
                continue;
            }
            if(str[0]>=97&&str[0]<=122&&str[2]>=97&&str[2]<=122&&(str[1]>='*'||str[1]<='+'||str[1]>='-'))
                return 3;
            cout<<"Error3"<<endl;
            cout<<str<<endl;
            exit(0);




        }
    }


    return 0;
}

int main()
{
    string str, command;
    cout << R"(Would u like to get input from "input.txt"? Y/N)" << endl;
    cin>>str;
    if (str[0] == 'Y') {
        cout << R"(Searching for it...)" << endl;
        ifstream input ("input.txt", ifstream::in);
        if (input.fail()) {
            cout << "File is not certain." << endl;
            return 0;
        }
        getline(input, command);
    } else if (str[0] == 'N') {
        cout << R"(Then type the string!)" << endl;
        cin>>command;
    } else {
        cout << "Try once again..." << endl;
        return 0;
    }

    cout<<command<<endl;
    fun(command);

    cout<<"mission complete"<<endl;
    return 0;
}