#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <cstring>
#include <numeric>
#include <algorithm>
#include <functional>
#include <array>
#include <map>
#include <queue>
#include <limits.h>
#include <set>
#include <stack>
#define rep(i,s,n) for(int i = (s); (n) > i; i++)
#define REP(i,n) rep(i,0,n)
#define RANGE(x,a,b) ((a) <= (x) && (x) <= (b))
#define POWT(x) ((x)*(x))
#define ALL(x) (x).begin(), (x).end()
#define MOD 1000000007
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;

int main() {
	int t;
	scanf("%d", &t);
	REP(i, t) {
		char str[1001];
		scanf("%s", str);
		int len = strlen(str);
		while (1) {
			if (len == 1) break;
			REP(j, len - 1) {
				int ss = (str[j] - '0') + (str[j + 1] - '0');
				ss = ss % 10 + (ss / 10);
				str[j] = ss + '0';
			}
			len--;
		}
		printf("%c\n", str[0]);
		
	}
	return 0;
}