#include<stdio.h>
int p,k,i,nrt,uc,pc,v1[11],v2[11];
char ch,chp,chpp;
int main()
{
    freopen("cifra.in","r",stdin);
    freopen("cifra.out","w",stdout);
    scanf("%d",&p);
    scanf("%c",&ch);
    v1[1]=1;
    v1[2]=5;
    v1[3]=2;
    v1[4]=8;
    v1[5]=3;
    v1[6]=9;
    v1[7]=2;
    v1[8]=8;
    v1[9]=7; 
    
    v2[1]=1;
    v2[2]=7;
    v2[3]=0;
    v2[4]=6;
    v2[5]=1;
    v2[6]=7;
    v2[7]=4;
    v2[8]=8;
    v2[9]=7;
    
    for(k=1;k<=p;k++)
    {
        scanf("%c",&ch);
        chpp=ch;
        if(scanf("%c",&ch)!=EOF && ch!='\n')
        {
                                 chp=ch;
                                 nrt=0;
                                 while(scanf("%c",&ch)!=EOF &&ch!='\n')
                                 {
                                                             chpp=chp;
                                                             chp=ch;
                                 }
                                 pc=(int)chpp-(int)'0';
                                 if(pc%2==0)
                                 {
                                   nrt=pc*7/2+pc*4;
                                   nrt=nrt%10;
                                   uc=(int)chp-(int)'0';
                                   nrt+=v2[uc];
                                   nrt=nrt%10;
                                   printf("%d\n",nrt);
                                 }
                                 else
                                 {
                                   nrt=((pc/2)+1)*7+pc*4;
                                   nrt=nrt%10;
                                   uc=(int)chp-(int)'0';
                                   nrt+=v1[uc];
                                   nrt=nrt%10;
                                   printf("%d\n",nrt);
                                 }
        }
        else
        {
            nrt=0;
            uc=(int)chpp-(int)'0';
            printf("%d\n",v1[uc]);
        }
    }
    return 0;
}