import sys
from collections import defaultdict, deque

def main():
    input = sys.stdin.read().split()
    idx = 0
    H = int(input[idx]); idx +=1
    W = int(input[idx]); idx +=1
    
    matrix = []
    elements = defaultdict(list)
    for i in range(H):
        row = list(map(int, input[idx:idx+W]))
        idx += W
        matrix.append(row)
        for j in range(W):
            v = row[j]
            if v != 0:
                elements[v].append((i, j))
    
    sorted_values = sorted(elements.keys(), reverse=True)
    total_ops = 0
    
    for v in sorted_values:
        nodes = elements[v]
        rows = set()
        cols = set()
        edges = defaultdict(list)
        for (i, j) in nodes:
            rows.add(i)
            cols.add(j)
            edges[i].append(j)
        
        graph = {}
        for u in rows:
            graph[u] = edges[u]
        
        match_U = {}
        match_V = {}
        dist = {}
        
        def bfs():
            queue = deque()
            for u in graph:
                if u not in match_U:
                    dist[u] = 0
                    queue.append(u)
                else:
                    dist[u] = float('inf')
            dist[None] = float('inf')
            while queue:
                u = queue.popleft()
                if u is not None:
                    for v in graph.get(u, []):
                        if dist.get(match_V.get(v), float('inf')) == float('inf'):
                            dist[match_V.get(v)] = dist[u] + 1
                            queue.append(match_V.get(v))
            return dist[None] != float('inf')
        
        def dfs(u):
            if u is not None:
                for v in graph.get(u, []):
                    if dist.get(match_V.get(v), float('inf')) == dist[u] + 1:
                        if dfs(match_V.get(v)):
                            match_U[u] = v
                            match_V[v] = u
                            return True
                dist[u] = float('inf')
                return False
            return True
        
        result = 0
        while bfs():
            for u in graph:
                if u not in match_U:
                    if dfs(u):
                        result +=1
        total_ops += result
    
    print(total_ops)

if __name__ == "__main__":
    main()