program z9_35;
var
s,z:string;
s1,sk:string[26];
a: array[1..30] of string[26];
i,j,m:integer;
begin
writeln('Ââåäèòå òåêñò');
readln(s);
s:=s+'.';
z:=', -;:!?.';
j:=0;
s1:='';
for i:=1 to length(s) do
if pos(s[i],z)=0 then s1:=s1+s[i]
else begin
j:=j+1;
a[j]:=s1;
s1:='';
end;
for i:=1 to j-1 do
if a[i]<>a[j] then begin
sk:='';
for m:=97 to 96+length(a[i]) do
sk:=sk+chr(m);
if a[i]=sk then writeln(a[i]);
end;
End.