#include <iostream>
using namespace std;
int main(){
    int t;cin>>t;
    while(t--){
        string s;cin>>s;
        string tmps = "";
        while(s.size() != 1){
            for(int i = 0; s.size()-1 > i; i++){
                int z = (((s[i]-'0')+(s[i+1]-'0'))%10);
                if((s[i]-'0')+(s[i+1]-'0') > 9)z++;
                tmps.push_back(z+'0');
            }
            s = tmps;
            tmps = "";
        }
        cout << s << endl;
    }
}