Read this article and answer this question After long negotiations the territorial changes resulting from the conflict were firmly established at the Treaty of Quedlinburg of 13 May 1523. The main import of these changes were significant gains for the princes of Brunswick-Wolfenbuttel, whilst the Prince-Bishopric of Hildesheim was left with just 4 of its original 22 districts as well as the towns of Hildesheim and Peine, the so-called Kleines Stift of some 90 villages. The ecclesiastical boundary of the diocese remained unchanged. The Principality of Brunswick-Wolfenbuttel was awarded the Amter of Winzenburg, Wohldenberg, Steinbruck, Lutter, Wohlenstein, Schladen, Liebenburg, Wiedelah, Vienenburg and Westerhof with the abbeys of Lamspringe, Heiningen, Dorstadt, Woltingerode, Ringelheim and Riechenberg, as well as the towns of Alfeld, Bockenem, Lamspringe and Salzgitter. The Principality of Calenberg received the houses, i.e.fortified seats, and Amter of Hunnesruck with Markoldendorf, Aerzen, Lauenstein, Grohnde, Hallerburg, Poppenburg, Ruthe and Coldingen, the towns of Dassel, Bodenwerder, Gronau, Elze, Sarstedt, half of Hameln and the abbeys of Marienau, Escherde, Wittenburg, Wulfinghausen and Derneburg. Hildesheim immediately began a legal fight for the return of its Groes Stift . This finally ended in 1643 in the Main Treaty of Hildesheim with a revision of the Treaty of Quedlinburg and return of most of the territories. Exceptions were the Amter of Aerzen, Grohnde, Coldingen-Lauenberg, Lutter am Barenberge, Westerhof and Lindau, which remained with the principalities of Calenberg and Brunswick-Wolfenbuttel. Prince-bishop John IV gave up the prince-bishopric in 1527 and later became canon of Ratzeburg and died in 1547 in Lubeck.
How many districts did Prince-Bishopric of Hildesheim lose in the conflict?
18