// No.432 占い(Easy)
// https://yukicoder.me/problems/no/432
//
#include <iostream>
#include <string>
using namespace std;

int solve(string &s);


int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    int T;
    cin >> T;
    string s;
    for (int i = 0; i < T; ++i) {
        cin >> s;
        int ans = solve(s);
        cout << ans << endl;
    }
}

int solve(string &s) {
    while (s.size() > 1) {
        size_t cs = s.size();
        for (int i = 1; i < cs; ++i) {
            int tmp = (s[i-1] - '0') + (s[i] - '0');
            while (tmp >= 10)
                tmp = (tmp % 10) + 1;
            s[i-1] = tmp + '0';
        }
        s.resize(cs - 1);
    }
    return s[0] - '0';
}