from sys import stdin
input=lambda :stdin.readline()[:-1]

h,w,n=map(int,input().split())
c=[]
for i in range(h):
  c.append(list(map(lambda x:int(x)-1,input().split())))

frm=[set() for i in range(n)]
dxdy=[(1,0),(0,1),(-1,0),(0,-1)]
for x in range(h):
  for y in range(w):
    for dx,dy in dxdy:
      nx,ny=x+dx,y+dy
      if 0<=nx<h and 0<=ny<w:
        if c[x][y]>c[nx][ny]:
          frm[c[x][y]].add(c[nx][ny])

color=[-1]*n
tmp=1
for i in range(n):
  ng=False
  for j in frm[i]:
    if tmp==color[j]:
      ng=True
  if ng:
    tmp+=1
  color[i]=tmp

print(tmp)