VAR a, b: integer;
begin
Readln (a);
b:= a div 10;
a:= a mod 10;
If (a+b)>9 then write ('yes')
else write ('no');
End.
VAR a, b: integer;
begin
Readln (a);
b:= a div 10;
a:= a mod 10;
If (a+b)>9 then write ('yes')
else write ('no');
End.