uses sysutils;

const
    n = 511;
{ or 512 }

var
    x : array [1..n] of string;
    i, j, k, t : integer;
begin
    for i := 1 to n do begin
        x[1] := x[1] + 'a';
    end;
    for i := 2 to n do begin
        x[i] := x[1];
        x[i][2] := 'b';
    end;
    for i := 2 to n do begin
        x[i][2] := 'a';
    end;
    k := 0;
    for t := 1 to 200 do begin
        for i := 1 to n do begin
            for j := 1 to n do begin
                if x[i] = x[j] then begin
                    inc(k);
                end;
            end;
        end;
    end;
    writeln(k);
end.