H,W,N = map(int, input().split())
ans = 1

c = [list(map(int, input().split())) for _ in range(H)]

ran = []
for i in range(H):
    for j in range(W-1):
        a = c[i][j]
        b = c[i][j+1]
        if(a!=b):
            if(a<b):
                a,b = b,a
            ran.append((a << 31) + b)

for i in range(H-1):
    for j in range(W):
        a = c[i][j]
        b = c[i+1][j]
        if(a!=b):
            if(a<b):
                a,b = b,a
            ran.append((a << 31) + b)

ran.sort()
mx = 0
for e in ran:
    l, r = e & ((1 << 31) - 1), (e >> 31)

    if(l >= mx):
        mx = r
        ans += 1

print(ans)