from sys import stdin
pin=stdin.readline

def main():
  H,W,N=map(int,pin().split())
  C=[list(map(int,pin().split()))for _ in[0]*H]
  d=[[]for _ in[0]*N]
  for i in range(H):
    for j in range(W):
      C[i][j]-=1
      d[C[i][j]].append((i,j))
  ans=1
  start=0
  around=((1,0),(0,1),(-1,0),(0,-1))
  for i in range(N):
    flag=True
    for x,y in d[i]:
      for dx,dy in around:
        if 0<=x+dx<H and 0<=y+dy<W and start<=C[x+dx][y+dy]<C[x][y]:
          ans+=1
          flag=False
          start=C[x][y]
          break
      if not flag:
        break
  print(ans)
  return

main()