QRegExp help

[Lele]

Hi all,
maybe this is not only a Qt question.
I'm using QRegExp for replace any occourrence of a word composed by one or two letters.
I don't get what expected, what I'm doing wrong?
thanks for any help/

QString resS = QString("a la test da che da me asdf non va");
resS.replace(QRegExp("[a-z]{1,2}"), "X");

QString resS = QString("a la test da che da me asdf non va");
resS.replace(QRegExp("[a-z]{1,2}"), "X");

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I get this:
X X XX X XX X X XX XX X

instead of
X X test X che X X asdf non X