#include<iostream>
#include<fstream>
#include <stdlib.h>
#include<string>
#include <ctime>

using namespace std;

int cifra_put(int num)
{
	int i,cifra;
	
	num=num%100;
	cifra=1;
	for (i=1;i<=num;i++)
	{
		cifra=(cifra*num)%10;
	}
	if (num==0)
		cifra=0;
	return (cifra);
}

int main()
{
	ifstream f("cifra.in");
	ofstream g("cifra.out");    
		
	clock_t start, end;
	int i,t,s,j,nr;
	string snr;
	start = clock();
	f>>t;
	for(i=1; i<=t; i++)
	{
		f>>snr;
		snr="0"+snr;
		snr=snr.substr(snr.length()-2);
		nr=atoi(snr.c_str());
		s=0;
		for(j=1; j<=nr; j++)    
			s=s+cifra_put(j);
		s=s%10;
		    
		g<<s<<endl;  
	}    
	end = clock();
	
	cout << endl << "Timp de executzie: "
	<< (double)(end-start)/CLOCKS_PER_SEC << " seconds." << "\n\n" ;	
	f.close();
	g.close();
}