Treasure Hunt

An area named Renus, is divided into $(N \times M)$ cells. According to archaeological survey the area contains huge amount of treasure. Some cells out of $(N \times M)$ cells contain treasure. But problem is, you can't go to every cell as some of the cells are blocked. For every $a_{ij}$ cell($1 \leq i \leq N$,$1 \leq j \leq M$), your task is to find the distance of the nearest cell having t