#include <cstdio>
#include <cctype>

using namespace std;

int p[] = {0,1,5,2,8,3,9,2,0,1};

int main(){
    FILE *fin, *fout;
    int t,i,cf1,cf2,suma;
    char ch;
    fin = fopen("cifra.in","r");
    fscanf(fin,"%d\n",&t);
    fout = fopen("cifra.out","w");
    for (i=0;i<t;i++) {
        ch = fgetc(fin);
        cf1 = cf2 = '0';
        while (isdigit(ch)) {
            cf1 = cf2;
            cf2 = ch;
            ch = fgetc(fin);
        }
        cf2 -= '0';
        cf1 -= '0';
        suma = p[9] * cf1 + p[cf2];
        suma %= 10;
        fprintf(fout,"%d\n",suma);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}