mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    d = [(0, 1), (0, -1), (-1, 0), (1, 0)]

    H, W, N = map(int, input().split())
    C = []
    for _ in range(H):
        C.append(list(map(int, input().split())))

    P = [[] for _ in range(N+1)]
    for h in range(H):
        for w in range(W):
            P[C[h][w]].append((h, w))

    ans = 1
    prev = 1
    for c in range(2, N+1):
        flg = 0
        for h, w in P[c]:
            for dh, dw in d:
                h_new, w_new = h + dh, w + dw
                if 0 <= h_new < H and 0 <= w_new < W:
                    if C[h_new][w_new] == prev:
                        flg = 1
        if flg:
            ans += 1
            prev = c
    print(ans)


if __name__ == '__main__':
    main()