program cserelo;
var f:file of char;
    c, amit, amire:char;
    s:string;
begin
     readln(s);
     readln(amit);
     readln(amire);
     assign(f,s);
     reset(f);
     while not eof(f) do
     begin
          read(f,c);
          if c=amit then
                    begin
                      seek(f,filepos(f)-1);
                      write(f,amire)
                    end;
     end;
     readln
end.