#include <iostream>
#include <vector>
using namespace std;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int t;
    cin >> t;

    while (t--) {
        string str;
        cin >> str;
        vector<int> s(str.size()), s2(str.size());
        for (int i = 0; i < str.size(); i++) {
            s[i] = str[i] - '0';
        }

        for (int i = 0; i < s.size() - 1; i++) {
            for (int j = 0; j < s.size() - i - 1; j++) {
                s2[j] = s[j] + s[j + 1];
                if (s2[j] >= 10) {
                    s2[j] = 1 + s2[j] % 10;
                }
            }
            /*
            cout << i << "回目: ";
            for (int j = 0; j < s.size() - i - 1; j++) {
                cout << s[j] << " ";
            }
            cout << endl;
            */
            s = s2;
        }
        cout << s[0] << endl;
    }

    return 0;
}