import sys

# sys.setrecursionlimit(1000005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 62)

# md = 10**9+7
md = 998244353


h, w, n = LI()
cc = LLI1(h)

to=[[] for _ in range(n)]
for i in range(h):
    for j in range(w):
        u = cc[i][j]
        if i:
            v = cc[i-1][j]
            if cc[i][j] < cc[i-1][j]: to[u].append(v)
            if cc[i][j] > cc[i-1][j]: to[v].append(u)
        if j:
            v = cc[i][j-1]
            if cc[i][j] < cc[i][j-1]: to[u].append(v)
            if cc[i][j] > cc[i][j-1]: to[v].append(u)

nc = [1]*n
for u in range(n):
    nc[u]=max(nc[u],nc[u-1])
    for v in to[u]:
        nc[v] = max(nc[v], nc[u]+1)
print(nc[-1])