#include <iostream>
using namespace std;

char solva(string s) {
    int a, n = s.size();
    for (int i = 1; i < n; ++i) {
        for (int j = 0; j < n - i; ++j) {
            a = s[j] + s[j + 1]  - 96;
            s[j] = a > 9 ? a % 10 + 49 : a + 48;
        }
    }
    return s[0];
}

int main() {
    int n;
    string s;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> s;
        cout << solva(s) << endl;
    }
    return 0;
}