#include <iostream>
#include <vector>
#include <execution>
#include <algorithm>
#include <random>

using namespace std ;



int main()
{

	const string ALLOWED_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
	string guid;
	// Sample 5 characters from ALLOWED_CHARS.
	sample(ALLOWED_CHARS.begin(), ALLOWED_CHARS.end(), back_inserter(guid),
	  5, mt19937{ random_device{}() });

	cout << guid; // e.g. G1fW2


return 1 ;
}