program ucif;
var i,us,p,e,t,j,c,m1,m2,m:integer;f,g:text;a:array[1..100] of byte;n:string;
begin
assign (f,'cifra.in');reset(f);
assign (g,'cifra.out');rewrite(g);
readln(f,t);
for i:=1 to t do begin
    readln(f,n);
val(n[length(n)],m1,c);val(n[length(n)-1],m2,c);
j:=1;us:=0;m:=m2*10+m1;
repeat
p:=1;
  for e:=1 to j do
  p:= p*j mod 10;
 us:=(us+p) mod 10;
 inc(j);
 until j>m;
writeln(g,us);
end;
close(f);
close(g);
end.