I don't think there's no way you can positively tell which gear "jumped", it could be the crank, or either of the cam gears, if it were me at the very least I would turn it until you can get any 2 of the gears to line up correctly and then loosen the belt and try and get the other one on it's timing mark, BUT not being there to really inspect the belt for even the smallest damage from it jumping or even have the slightest thought that it might be damaged I might be inclined to go with a new belt because if the old belts breaks while it's running the engine will be trashed and then you're looking at replacing the engine.