ssm>function Check(str : string) : boolean;
ssm>type
ssm>  TState = (stNum, stLetter);
ssm>const
ssm>  ValidChars = ['а'..'я'];
ssm>  ValidNums = ['0'..'9'];
ssm>var
ssm>  i : integer;
ssm>  st : TState;
ssm>begin
ssm>  result := false;
ssm>  i := 1;
ssm>  st := stNum;
ssm>  while(i <= length(str)) do begin
ssm>    if(st = stLetter) then begin
ssm>      result := false;
ssm>      exit;
ssm>    end else if(st = stNum) then begin
ssm>      if(str[i] in ValidChars) then begin
ssm>        st := stLetter;
ssm>        result := true;
ssm>      end else if not(str[i] in ValidNums) then
ssm>        exit;
ssm>    end;
ssm>    inc(i);
ssm>  end;
ssm>  result := true;
ssm>end;
ssm>