#include <iostream>
#include <string>

int main()
{
    std::string str;

    std::cout << "Enter your text: " << std::endl;
    std::getline(std::cin, str);
    int number_of_a(0);
    for (int i = 0; i < str.length(); i++)
    {
        number_of_a = (str.at(i)=='a') ? (number_of_a+1) : number_of_a;
    }
    std::cout << number_of_a << std::endl;
    system("pause");
    return 0;
}