// primediv6.cpp : アプリケーションのエントリ ポイントを定義します。
//
#include <iostream>
#include <cmath>
#include <cstdint>
 
bool isPrime(std::uint64_t N) {//tekito-
	std::uint64_t L = std::sqrt(N) + 1;
 
	for (std::uint64_t i = 2; i < L; i++) {
		if (N%i == 0) return false;
	}
 
	return true;
}
 
std::uint64_t PrimeDiv6(std::uint64_t N) {
	if (!isPrime(N)) return N;
	double D = N;
	return std::round(D / 6) * 6;
}
 
 
int main()
{
 
	for (std::uint64_t i = 5; i <= 32; i++) {
 
		std::cout <<i<<':'<< PrimeDiv6(i) << std::endl;
	}
 
    return 0;
}
 

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