#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;

ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;
    return gcd(b, a % b);
}
int lcm(int a, int b) {
    return a * b / gcd(a, b);
}


int main()
{

    int Q;
    Q = 1;
    //cin >> Q;
    
    while (Q--) {

        int n;
        cin >> n;
        for (int i = 0; i < n; i++) {
            string a;
            cin >> a;
            vector<int>x;
            for (int i = 0; i < a.size(); i++) {
                x.push_back(a[i] - '0');
            }
            while (x.size()>1) {
                vector<int>t;
                for (int i = 0; i < x.size()-1; i++) {
                    int r = x[i] + x[i + 1];
                    while (r > 9) {
                        r %= 10; r++;
                    }
                    t.push_back(r);
                }
                x = t;
                if (x.size() == 1)break;
            }
            cout << x[0]<<endl;
        }

    }
    return 0;
}