<DataGrid.RowHeaderTemplate>
                <DataTemplate>
                    <Border>
                        <Border.Style>
                            <Style TargetType="Border">
                                <Style.Triggers>
                                    <DataTrigger Binding="{Binding Path=DataContext, RelativeSource={RelativeSource Self}, Converter={StaticResource borderConverter}}" Value="0">
                                        <Setter Property="BorderThickness" Value="0,0,0,2" />
                                        <Setter Property="BorderBrush" Value="Black" />
                                    </DataTrigger>
                                </Style.Triggers>
                            </Style>
                        </Border.Style>
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto" />
                                <ColumnDefinition Width="Auto" />
                            </Grid.ColumnDefinitions>
                            <TextBlock
                                Grid.Column="0"
                                Margin="3"
                                Text="{Binding Day, Converter={StaticResource englishToRussianWeekDayConverter}}" />
                            <TextBlock
                                Grid.Column="1"
                                Margin="3"
                                Text="{Binding Pair, Converter={StaticResource numberToTimeConverter}}" />
                        </Grid>
                    </Border>
                </DataTemplate>
            </DataGrid.RowHeaderTemplate>