program alex;
var f,g:text;
    s:string;
    er:integer;
    i,t,k,u,r,d,j,h,z,x,p:longint;
    c:array[0..200]of integer;

begin
assign(g,'cifra.out');rewrite(g);
assign(f,'cifra.in');reset(f);
readln(f,t);
for i:=1 to t do
    begin
    readln(f,s);
    k:=0;
    for j:=length(s) downto 1 do
        begin
        k:=k+1;
        val(s[j],c[k],er);
        end;
    r:=0;
    d:=0;
    for j:=k downto 1 do
        begin
        z:=c[j];
        c[j]:=(d*10+c[j])div 20;
        d:=(d*10+z)mod 20;
        r:=d;
        end;
    u:=(c[1]*4)mod 10;
    case r of
    1,17:u:=u+1;
    2,18:u:=u+5;
    3,7:u:=u+2;
    4,8,11,15:u:=u+8;
    5,14:u:=u+3;
    6:u:=u+9;
    9,10,13:u:=u+7;
    12,16,19:u:=u+4;
    end;
    u:=u mod 10;
    writeln(g,u);
    end;
close(f);
close(g);
end.