Program A;
uses crt;

 var 
s: string; 
k,j,f: integer; 
ch: char; 
begin 
read(S); 
f:=0; 
for k:=1 to length(s) do 
for j:=1 to length(s) do 
if ((s[k]=s[j]) and (k<>j)) then begin f:=1; ch:=s[k]; end; 
if f=1 then Writeln('YES - ',ch) else write('NO'); 
readln; 
End.