#include <iostream>
#include <stdexcept>
#include <cmath>

bool validNums(const int num1, const int num2) {
    if (num1 < 1 || num1 > 9 || num2 < 2 || num2 > 999999999)
        return false;
    else
        return true;
}

int divisbleBy(int num1, int num2) {
    for (; num1 != 0; --num1) {
        if (num1 % num2 == 0)
            return num1;
    }
    return 0;
}

int produceAnswer(int &num1, int num2) {
    int answer = 0;
    if (!validNums(num1, num2)) {
        return 0;
    }
    num1 = pow(10, num1) - 1; num2 = divisbleBy(num1, num2);
    if (num2 != 0)
        return num2;
    return 0;
}

int main()
{
    int num1 = 0, num2 = 0, answer = 0;
    std::cout << "Enter 2 nums and we'll find biggest number possible with num1 digits and we'll then find closest number that num2 can divide by." << std::endl;
    std::cout << " The first number? [From 1 to 9] "; std::cin >> num1;
    std::cout << "The second number? [From 2 to 999_999_999] "; std::cin >> num2;
    answer = produceAnswer(num1, num2);
    if (answer != 0)
        std::cout << "Larges number is " << num1 << " and closest number that divisible by it is " << answer << std::endl;
    else
        std::cout << "Invalid" << std::endl;
    return 0;
}