user123/SergechevExam/App.xaml

<Application x:Class="SergechevExam.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:SergechevExam"
             StartupUri="Windows/MainWindow.xaml">
    <Application.Resources>
         
    </Application.Resources>
</Application>