Снова D++

#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <vector>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <queue>
#include <stack>
#include <climits>
#include <deque>
#include <ctime>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;

int main()
{
    string s;
    ll f = 0, c = 0;
    stack<int>last;
    while (getline(cin, s))
    {
        for (int i = 0; i < s.size(); i++)
        {
            if (s[i] == '(')
            {
                if (!last.empty())
                {
                        if (s[i + 1] == '*'&&last.top() != 1)
                        {
                            c++;
                            i++;
                            last.push(1);
                        }
                        else
                            if (!last.empty())
                            {
                                if (last.top() != 1)
                                {
                                    last.push(0);
                                    f++;
                                }
                            }
                            else
                            {
                                last.push(0);
                                f++;
                            }
                }
                else
                    if (last.empty())
                    {
                        if (s[i + 1] == '*')
                        {
                            c++;
                            i++;
                            last.push(1);
                        }
                        else
                        {
                            last.push(0);
                            f++;
                        }
                    }
            }
            else
            {
                if (s[i] == '*')
                {
                    if (!last.empty())
                        if (last.top() == 1)
                            if (s[i + 1] == ')')
                            {
                                c--;
                                last.pop();
                                i++;
                            }
                }
                else
                    if (s[i] == ')')
                    {
                        if (f == 0 && c == 0)
                        {
                            cout << "NO";
                            return 0;
                        }
                        else
                            if (last.top() == 0)
                            {
                                f--;
                                last.pop();
                            }
                    }
                            else
                            {
                                if (!last.empty())
                                {
                                    if (last.top() == 0)
                                    {
                                        if ((s[i] < '0' || s[i] > '9') && s[i] != '*' && s[i] != '-' && s[i] != '+' && s[i] != '/'&&s[i] != '=')
                                        {
                                            cout << "NO";
                                            return 0;
                                        }
                                    }
                                }
                            }
            }
        }

    }
    if (c == 0 && f == 0)
    {
        cout << "YES";
    }
    else
        cout << "NO";


    return 0;
}