#include <stdio.h>
#include <ctype.h>
int v[10]={0,1,4,7,6,5,6,3,6,9};
int main()
{
    int i,t,sum,k,nr;
    char c1,c2,c3;
    freopen("cifra.in","r",stdin);
    freopen("cifra.out","w",stdout);
    scanf("%d",&t);
    getchar();
    for(i=1; i<=t; i++){
        c1=getchar();
        c2=getchar();
        if(isdigit(c2)){
            c3=getchar();
            while(isdigit(c3)){
                c1=c2;
                c2=c3;
                c3=getchar();
            }
            c1=c2;
            c2=c3;
        }
        c1-='0';
        c2-='0';
        if(!isdigit(c2+'0')) nr=c1;
        else nr=c1*10+c2;
        sum=0;
        for(k=1; k<=nr; k++)
            sum+=v[k%10];
        printf("%d\n",sum%10);
    }

    return 0;
}