#include <stdio.h>
#include <string.h>

int main(){
    int i, ls, rez, T;
    char s[100];
    int sum[10] = {0, 1, 5, 2, 8, 3, 9, 2, 8, 7};
    FILE *f = fopen("cifra.in", "r");
    FILE *g = fopen("cifra.out", "w");
    fscanf(f, "%d", &T);
    for(; T; --T) {
          fscanf(f, "%s", s);
          ls = strlen(s);
              rez = 0;
                  for(i=0; i<ls-1; i++)
                           rez = rez + ((s[i] - '0') * 9 ) %10;
           rez = rez + sum[s[ls-1]-'0'];
           fprintf(g, "%d\n", rez % 10);
           }
    fclose(g);
    fclose(f);
    return 0;
}