from collections import defaultdict

def dfs(v, visited):
    global edges, matched
    for u in edges[v]:
        if u in visited:
            continue
        visited.add(u)
        if matched[u] == -1 or dfs(matched[u], visited):
            matched[u] = v
            return True
    return False
    
def mpc(xn, yn):
    global matched, edges
    matched = [-1] * yn

    left = [True] * xn
    right = [False] * yn

    ledges = []
    redges = matched

    for v in range(xn):
        if not dfs(v, set()):
            left[v] = False
            ledges.append(v)
    for v in ledges:
        for u in edges[v]:
            right[u] = True
            if redges[u] >= 0:
                left[redges[u]] = False

    return sum(left+right)


if __name__ == '__main__':
    H, W = map(int, input().split())

    S = defaultdict(list)

    for i in range(H):
        for j, a in enumerate(list(map(int, input().split()))):
            if a > 0:
                S[a].append((i, j))
    
    cnt = 0
    for a, l in S.items():
        h , w = set(), set()
        for i, j in l:
            h.add(i)
            w.add(j)
        h, w = list(h), list(w)
        edges = [set() for _ in range(len(h))]
        for i, j in l:
            edges[h.index(i)].add(w.index(j))
        
        n = mpc(len(h), len(w))
        cnt += n
    
    print(cnt)