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

int main()
{
    int t,bla;
    FILE *fin, *fout;
    fin=fopen("cifra.in","r");
    fout=fopen("cifra.out","w");
    fscanf(fin,"%d",&t);
    for(bla=0;bla<t;bla++){
        char nr[101];
        fscanf(fin,"%s",nr);
        short int lnr=strlen(nr);
        unsigned char u1=nr[lnr-1]-'0',u2=(lnr>1?(nr[lnr-2]-'0'):0),s;
        s=(9*u2);
        switch(u1){
        case 1:
            s=(s+1)%10;
            break;
        case 2:
            s=(s+5)%10;
            break;
        case 3:
            s=(s+2)%10;
            break;
        case 4:
            s=(s+8)%10;
            break;
        case 5:
            s=(s+3)%10;
            break;
        case 6:
            s=(s+9)%10;
            break;
        case 7:
            s=(s+2)%10;
            break;
        case 8:
            s=(s+8)%10;
            break;
        case 9:
            s=(s+7)%10;
            break;
        default:
            s=s%10;
            break;
        }
        fprintf(fout,"%d\n",(int)s);
    }
    return 0;
}