不懂为什么MLE

var
f:array[1..10000]of integer;
n,x,y,z:integer;m:longint;

function find(x:integer):integer;
begin
if f[x]=0 then exit(x);
if f[f[x]]=0 then exit(f[x]);
find:=find(f[x]);
f[x]:=find;
end;

begin
read(n,m);
fillchar(f,n,0);
while m>0 do
begin
read(z,x,y);
case z of
1:f[find(y)]:=find(x);
2:if find(x)=find(y) then writeln('Y') else writeln('N');
end;
dec(m);
end;
end.