#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {
	int n;
	cin >> n;
	vector<string>p(n);
	
	for (int i = 0; i < n; i++) {
		string x;
		cin >> x;
		while (x.size() >= 2) {
			string h;
			
			for (int j = 0; j < x.size()-1; j++) {
				int y = x[j] - '0' + x[j + 1] - '0';
				if (y > 9)y++, y %= 10;
				h += ('0' + y);
				//cout << h << endl;
				
			}
			x = h;
		}
		p[i] = x;
	}
	for (int i = 0; i < n; i++)
		cout << p[i] << endl;

	return 0;


}