진수 변환

int convert_num (int no, int d) {
	vector <int> v;
	while(no != 0) {
		v.push_back(no%d);
		no /= d;
	}
	int ret = 0;
	for(int i=v.size()-1; i>=0; i--)
		ret += v[i] * pow(10, i);

	return ret;
}