#include <fstream>
#include <cstring>

using namespace std;
ifstream f ("cifra.in");
ofstream g ("cifra.out");
int S,i,n,r,j,t;
char x[104];
int main()
{   f>>t;
    for (j=1;j<=t;j++)
    {f>>x;
    if ((strlen(x)-1)>1)
    n=(x[strlen(x)-2]-'0')*10+(x[strlen(x)-1]-'0');
    else
    n=x[0]-'0';S=0;
    for (i=1;i<=n;i++)
    {if (i%10==1)
    S+=1;
    else
    if (i%10==2)
    {r=i%4;if(r==1)S+=2;else if (r==2)S+=4; else if (r==3)S+=8; else S+=6;}
    else
    if (i%10==3)
    {r=i%4;if(r==1)S+=3;else if (r==2)S+=9; else if (r==3)S+=7; else S+=1;}
    else
    if (i%10==4)
    {r=i%2;if(r==1)S+=4;else S+=6;}
    else
    if (i%10==5)
    S+=5;
    else
    if (i%10==6)
    S+=6;
    else
    if (i%10==7)
    {r=i%4;if(r==1)S+=7;else if (r==2)S+=9; else if (r==3)S+=3; else S+=1;}
    else
    if (i%10==8)
    {r=i%4;if(r==1)S+=8;else if (r==2)S+=4; else if (r==3)S+=2; else S+=6;}
    else
    if (i%10==9)
    {r=i%2;if(r==1)S+=9;else S+=1;}
    S=S%10;
    }
    g<<S%10<<'\n';
}
    return 0;
}