#include <stdio.h>
#include <cstring>
#include <cmath>
int cifra[101];
char ch[101],cht;
int main()
{
    cifra[0]=0;
    cifra[1]=1;
    cifra[2]=5;
    cifra[3]=2;
    cifra[4]=8;
    cifra[5]=3;
    cifra[6]=9;
    cifra[7]=2;
    cifra[8]=8;
    cifra[9]=7;
    cifra[10]=7;
    FILE *fin,*fout;
    fin=fopen("cifra.in","r");
    fout=fopen("cifra.out","w");
    for(int i=11;i<=99;i++)
    {
        cifra[i]=cifra[i-1];
        int nr=i%10;
        for(int j=1;j<i;j++)
        {
            nr*=(i%10);
            nr%=10;
            if(nr==0) break;
        }
        cifra[i]+=nr;
        cifra[i]%=10;
    }
    int t;
    fscanf(fin,"%d",&t);
    for(int i=0;i<t;i++)
    {
        fscanf(fin,"%c",&cht);
        fscanf(fin,"%s",ch);
        int s=strlen(ch);
        if(s==1) fprintf(fout,"%d\n",cifra[ch[0]-'0']);
        else
        {
           int nr=(ch[s-2]-'0');
            nr*=10;
            nr+=(ch[s-1]-'0');
            fprintf(fout,"%d\n",cifra[nr]);
        }
    }
}