void 友数对友质数()
{//缘由https://bbs.csdn.net/topics/396498706?page=1#post-411382586
	int aa = 2, aaa = 20; while (aa * aaa <= 119)if (判断质数(aa * aaa - 1))cout << aa << ends << aaa << ends << (aa*aaa - 1) << endl, ++aaa; else ++aaa;
}