#!/usr/bin/python3

n,m = map(int,input().split(' '))

park = []

for r in range(n):
    park.append(list(map(int,input().split(' '))))

#print(park)

linear = []
for r in park:
    for c in r:
        if c != -1:
            linear.append(c)

linear.sort()
rev = []
for l in linear:
    rev.append(l)

rev.reverse()

#print('forward',linear)
#print('reverse',rev)

count1 = 0
count2 = 0
diag = []

for c in range(-n+1,m):
    r = n - 1
    c2 = c

    while r >= 0:
        if 0 <= c2 < m and park[r][c2] != -1:
            diag.append(park[r][c2])
        r -= 1
        c2 += 1

for i in range(len(linear)):
    if linear[i] != diag[i]:
        count1 += 1
    if rev[i] != diag[i]:
        count2 += 1

count3 = 0
count4 = 0
diag = []

for c in range(m+n-1):
    r = n - 1
    c2 = c

    while r >= 0:
        if 0 <= c2 < m and park[r][c2] != -1:
            diag.append(park[r][c2])
        r -= 1
        c2 -= 1

for i in range(len(linear)):
    if linear[i] != diag[i]:
        count3 += 1
    if rev[i] != diag[i]:
        count4 += 1

#print(count1,count2,count3,count4)

best = count1
if count2 < best:
    best = count2
if count3 < best:
    best = count3
if count4 < best:
    best = count4

print(best)