#include <bits/stdc++.h>
#define Dim 102
using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
int T,ans,V[12];
char N[Dim];

int main()
{
    V[1]=1; V[2]=4; V[3]=7; V[4]=6; V[5]=5; V[6]=6; V[7]=3; V[8]=6; V[9]=9;
    f>>T; f.get();
    for(int i=1;i<=T;i++)
    {
        ans=0;
        f.get(N,Dim);
        f.get();
        int lg=strlen(N)-1;
        int c1=atoi(&N[lg-1]);
        int ramas=atoi(&N[lg]);
 //cout<<i<<" "<<c1<<" "<<ramas<<'\n';
        ans+=c1+( (4*c1)%10 )+( (5*c1)%10 )+( (6*c1)%10 )+( (9*c1)%10 );
        if(c1%2!=0)
        ans+=4+7+3+6;
       // cout<<'\n';
        for(int j=1;j<=ramas;j++)
        {
           ans+=V[j];
        }
       // cout<<'\n'<<'\n'<<'\n';
        ans%=10;
        g<<ans<<'\n';
    }
    return 0;
}