I could not run 'flutter doctor' in command prompt. please check attached screenshot.

and if i try to run app , then i am getting following error.

Launching lib\main.dart on SM G920I in debug mode...
Initializing gradle...
Resolving dependencies...
Finished with error:

*** Error running Gradle:
Unable to download needed Android SDK components, as the following licenses have not been accepted:
Android SDK Build-Tools 26.0.2, Android SDK Platform 27

To resolve this, please run the following command in a Terminal:
flutter doctor --android-licenses**