r,c=map(int,input().split())
a=[[int(x) for x in input().split()]for i in range(r)]
nr=[-1,-1,0,1,1,1,0,-1]
nc=[0,1,1,1,0,-1,-1,-1]
f=0
for i in range(r):
    for j in range(c):
        out=True
        for k in range(8):
            x=j+nc[k]
            y=i+nr[k]
            if x>=0 and y>=0 and x<=(c-1) and y<=(r-1) and a[i][j]==a[y][x]:
                out=False
                break
        if out:
            f+=1
print(f)