// PAVEL_MELL.cpp : Этот файл содержит функцию "main". Здесь начинается и заканчивается выполнение программы.
//

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


int main()
{
    setlocale(0, "");
    int mark = 0,  i;
    bool EO_line = false;
    int difference = 0;
    int mas[4][5] = {
        // 0  1  a   b  \0
        { 0, 1, 2, 3, -2},//0
        { -1, 1, 2, -1, -2 },//1
        { -1, -1, 2, 3, -2 }, //2
        { -1, -1, -1, 3, -2 } };//3
    string sequence;
    cin >> sequence;
    for (i = 0; i <= sequence.length(); i++) {

        switch (sequence[i]) {
        case '0': mark = mas[mark][0];
                  break;
        case '1': mark = mas[mark][1];
                  break;
        case 'a': {
            mark = mas[mark][2];
            difference++;
            break;
        }
        case 'b': {
            mark = mas[mark][3];
            difference--;
            break;
        }
        case '\0': mark = mas[mark][4];
                   break;
        default: mark = -1;
                 break;
        }
        if (mark == -2) {
            EO_line = true;
            break;
        }
        if (mark == -1) {
            break;
        }
    }
    if (difference > 0)
        cout<< endl << "No, error in markition " << i + 1 << " = " << sequence[i] << endl;
    else if (difference < 0)
        cout << endl<< "No, error in markition " << i + 1 + (difference) << " = " << sequence[i + difference] << endl;
    else if (not EO_line) {
        cout << endl << "No, error in markition " << i + 1 << " = " << sequence[i] << endl;
    }
    else {
        cout << "Yes" << endl;
    }
    //system("pause");
    return 0;
}