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

int check(string s) {
	string t;
	if (s.length() == 1) {
		return s[0] - '0';
	}
	do {
		for (int i = 0; i < s.length() - 1;i++) {
			int x = ((s[i] - '0') + (s[i + 1] - '0'));
			if (x < 10) {
				t += (x + '0');
			}
			else {
				t += (1 + x % 10 + '0');
			}
		}
		if (t.length() == 1) { return t[0] - '0'; }
		s = t;
		t.clear();
	} while (1);
}

int main() {
	cin.tie(0); ios::sync_with_stdio(false);
	int T; cin >> T;
	vector<string> S(T);
	for (int i = 0; i < T; i++) {
		cin >> S[i];
		//cout << check(S[i]) << endl;
	}
	for (int i = 0; i < T;i++) {
		cout << check(S[i]) << endl;
	}
	return 0;
}