백준 11050 c++

#include <iostream>

using namespace std;

int input(int lower, int upper);

int main(void)
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int N, K, numerator = 1, denominator = 1;
	
	N = input(1, 10);
	K = input(0, N);
	for (int i = 0; i < K; i++)
	{
		numerator = numerator * (N - i);
	}
	for (int i = 0; i < K; i++)
	{
		denominator = denominator * (K - i);
	}
	cout << numerator / denominator << "\n";
	
 
	return 0;
}

int input(int lower, int upper)
{
	//cout << "input" << endl;
	int A;

	while (1)
	{
		cin >> A;
		if (A >= lower && A <= upper)
		{
			break;
		}
		else
		{
			;
		}
	}

	return A;
}