I don't understand why WA #1 because I fully tested answer of mu programm and answer on site. They hasn't got differences! Even invisible characters. Here is my code:

var n,i,j,fl,k,n1:longint; a,b,d,x:string; y,z:array [1..100] of string;
z1:array [1..100] of byte; c:char;
begin
readln (n);
for i:=1 to n do begin
fl:=0;
a:=''; b:=''; d:='';
readln (x);
n1:=length (x);
j:=0;
repeat
j:=j+1;
If x[j]<>' ' then a:=a+x[j];
until x[j]=' ';
repeat
j:=j+1;
If x[j]<>' ' then b:=b+x[j];
until x[j]=' ';
repeat
j:=j+1;
If x[j]<>' ' then d:=d+x[j];
until j>=n1;
fl:=0;
If a='register' then begin
for j:=1 to k do
If b=y[j] then fl:=1;
If fl=1 then writeln ('fail: user already exists') else begin
writeln ('success: new user added'); k:=k+1; y[k]:=b; z[k]:=d; z1[k]:=0;end;end;
fl:=0;
If a='login' then begin
for j:=1 to k do
If b=y[j] then fl:=j;
If fl=0 then writeln ('fail: no such user') else
If (fl>0) and (d<>z[fl]) then writeln ('fail: incorrect password') else
If (fl>0) and (d=z[fl]) and (z1[fl]=1) then writeln ('fail: already logged in') else begin
writeln ('success: user logged in'); z1[fl]:=1;end;end;
fl:=0;
If a='logout' then begin
for j:=1 to k do
If b=y[j] then fl:=j;
If fl=0 then writeln ('fail: no such user') else
If (fl>0) and (z1[fl]=0) then writeln ('fail: already logged out') else begin
writeln ('success: user logged out'); z1[fl]:=0;end;end;end;
end.