What is there in this test?
This solution now gets WA38

var
 ar : array[1..10,0..9] of longint;
 n,i,a1,a,j,max : longint;
begin
readln(n);
for j := 1 to n do
 begin
  readln(a);
  i := 1;
  while a <> 0 do
   begin
    a1 := a mod 10;
    a := a div 10;
    inc(ar[i,a1]);
    inc(i);
   end;
 end;
n := 0;
for i := 10 downto 1 do
 begin
  max := 0;
  for j := 1 to 9 do
   if ar[i,j] > ar[i,max] then
    max := j;
  n := n*10 + max;
 end;
writeln(n);
end.