#include <bits/stdc++.h>
using namespace std;

int main()
{
	int T;
	cin >> T;

	for( int t = 0; t < T; t++ ) {
		string S;
		cin >> S;
		for( int s = S.size(); s > 1; s-- ) {
			for( int i = 0; i < s - 1; i++ ) {
				int n1 = S[i] - '0';
				int n2 = S[i + 1] - '0';
				int n = n1 + n2;
				if( n >= 10 ) n = n % 10 + n / 10;
				S[i] = (char)(n + '0');
			}
		}
		char ans = S[0];
		cout << ans << endl;
	}
}