#include <iostream>
#include <string>
using namespace std;

bool isExpressionValid(string expression);
bool wyrazenie(string expression);
char operators[5]={'+','-','*','/','^'};

int main()
{
    string expression;
    cout << "Enter the expression: " << endl;
    getline(cin,expression);
    if(isExpressionValid(expression))
        cout << "The expression is valid" << endl;
    else
        cout << "The expression is faulty!" << endl;
    return 0;
}


bool isExpressionValid(string expression)
{
    int bracketsCounter = 0;
    int charactersCounter=0;
    int operatorsCounter=0;
    bool lastOperator=false;
    bool lastCharacter=false;
    for(int i = 0; i < expression.size(); i++){
        if(expression[i]=='('){
            lastOperator=false;
            lastCharacter=false;
            bracketsCounter++;
        }
        if(expression[i]==')'){
            bracketsCounter--;
            lastOperator=false;
            lastCharacter=false;
            if(lastOperator) return false;
            if(bracketsCounter < 0) return false;
        }
        if((expression[i]>='A' && expression[i] <= 'Z') || (expression[i]>='a' && expression[i] <= 'z')){
            if(!lastCharacter){
                charactersCounter++;
                lastCharacter=true;
                lastOperator=false;
            }
        }
        for(int j = 0; j < 5; j++){
            if(expression[i]==operators[j]){
                operatorsCounter++;
                if(lastOperator){
                    return false;
                }
                lastCharacter=false;
                lastOperator=true;
            }
        }
    }
    cout << "Liczba operatorow: " << operatorsCounter << endl;
    cout << "Liczba zmiennych: " << charactersCounter << endl;
    if(bracketsCounter!=0) return false;
    if(lastOperator) return false;
    return true;
}