Installing android-sdk doesn't install the sdkmanager tool

I'm using Ubuntu 18.04. I installed the Android SDK using:

```
    sudo apt-get update
    sudo apt-get install android-sdk
```

However, I'm stuck at this error I'm getting while trying to build my app with Gradle:

```
Checking the license for package Android SDK Build-Tools 25.0.1 in /usr/lib/android-sdk/licenses
Warning: License for package Android SDK Build-Tools 25.0.1 not accepted.
Checking the license for package Android SDK Platform 25 in /usr/lib/android-sdk/licenses
Warning: License for package Android SDK Platform 25 not accepted.

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':app'.
> You have not accepted the license agreements of the following SDK components:
  [Android SDK Build-Tools 25.0.1, Android SDK Platform 25].
  Before building your project, you need to accept the license agreements and complete the installation of the missing components using the Android Studio SDK Manager.
  Alternatively, to learn how to transfer the license agreements from one workstation to another, go to http://d.android.com/r/studio-ui/export-licenses.html
```

According to StackOverflow, the way to fix this is to do `yes | $ANDROID_HOME/tools/bin/sdkmanager --licenses`. However there's no sdkmanager in tools/bin! Also, there's no `android` executable if I try to run `android update sdk ...` instead.

Please help?