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

int main() {
	int t;
	cin >> t;
	string s;

	while(t-- > 0){
		cin >> s;
		
		while(s.length() > 1){
			string next = "";
			
			for(int i = 0; i < s.length() - 1; i++){
				int tmp = (s[i] - '0') + (s[i+1] - '0');

				if(tmp >= 10) tmp -= 9;
				
				next += to_string(tmp);
			}
			
			s = next;
		}
		
		cout << s << endl;
	}

	return 0;
}