24. 已知复数zzz满足∣z−3i∣+∣z+2∣=13\vert {z-3i}\vert +\vert {z+2}\vert =\sqrt{13}∣z−3i∣+∣z+2∣=13,则∣z−1∣\vert z-1\vert∣z−1∣的最小值是 .