paintEvent - execute four times

[pajczur]

Hello,
I have some strange problem.
I have empty project, just clicked "New QT Widget Application", and after I execute that code:

void MainWindow::paintEvent(QPaintEvent *e)
{
    cout << 1 << endl;
}

void MainWindow::paintEvent(QPaintEvent *e)
{
    cout << 1 << endl;
}

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I get result like:
1
1
1
1

So it looks like paintEvent function is repeated 4 times automaticaly. Why does it work like that? Can't I change it in some way to just one execution?

For any help thanks in advance.
Best Regards