-(void) createSecondViewController{
    
    NSLog(@"createSecondViewController is called");
    
    DTSecondViewController* secondViewController=[[DTSecondViewController alloc]initWithGradeAndArray:self.grade mutArr:self.coefficientsValuesArray];// Кастомная
    
    secondViewController.view.backgroundColor     =[UIColor lightGrayColor];
    [self presentViewController:secondViewController animated:YES completion:^{
        NSLog(@"present VC is chacged");
    } ];
}//createSecondViewController