#include <stdio.h>

int main()
{
	int Test; scanf("%d", &Test); while (Test--){
		char S[1010];
		scanf ("%s",S);
		int l = 0;
		while (S[l]) l++;
		for (int i=l;i>=2;i--){
			for (int j=0;j<i-1;j++){
				int u = S[j] - '0' + S[j+1] - '0';
				if (u >= 10) u -= 9;
				S[j] = u + '0';
			}
		}
		putchar(S[0]);
		puts("");
	}

	return 0;
}