Complex sentence: Mūša is a river in Northern Lithuania, having it's joint mouth with river Nemunėlis (Latvian: Mēmele), in Latvia, near city Bauska, Mūša is a tributary to the river Lielupė.
Split into simpler sentences: Mūša is a river in Northern Lithuania, having it's mouth in Latvia, near city Bauska. Having joint mouth with river Nemunėlis (Latvian: Mēmele), Mūša is tributary to the river Lielupė.