Ответ:

var s: string;

i:integer;

begin

readln(s);

for i:=1 to length(s) do if s[i]=',' then s[i]:='.';

write(s)

end.

===== PascalABC.NET =====

begin

 var s := ReadlnString;

 s := s.Replace(',', '.');

 Println(s)

end.