Complex sentence: Three major assaults on Gvozdansko were repelled on 10,11 and 12 January, leaving only around 30 men still alive that held their positions on the last days of the siege.
Split into simpler sentences: Three major assaults on Gvozdansko were repelled on 10,11 and 12 January. Around 30 men were still alive and held their positions on the last days of the siege.