seen = []
szint = []
graf = []
n, m, s = 0, 0, 0

def Init():
    for _ in range(n*m):
        l = []
        graf.append(l)
        seen.append(False)
        szint.append(0)

def Check():
    for i in range(n):
        print ''.join(matrix[i][j] for j in range(m))

def Check2():
    for i in range(n*m):
        print ''.join(str(graf[i][j]) for j in range(len(graf[i])))

def ElvagoEl(x, sz):
    seen[x] = True
    szint[x] = sz
    rfminvm = 1000000
    uminvm = 0
    global s

    for i in range(len(graf[x])):
        if not seen[graf[x][i]]:
            uminvm = ElvagoEl(graf[x][i], sz+1)
            if uminvm <= szint[x]:
                if uminvm < rfminvm:
                    rfminvm = uminvm
        if seen[graf[x][i]]:
            if szint[graf[x][i]] < szint[x]-1:
                     if szint[graf[x][i]] < rfminvm:
                         rfminvm = szint[graf[x][i]]
    if rfminvm != 1000000:
        s+=1
    return rfminvm
    

if __name__ == '__main__':
    matrix = []
    ch = raw_input().split(' ')
    n = int(ch[0])
    m = int(ch[1])

    for i in range(n):
        l = []
        ch = raw_input()
        for j in range(m):
            l.append(ch[j])
        matrix.append(l)
        
    Init()

    for i in range(n-1):
        for j in range(m-1):
            if matrix[i][j] == '1' and matrix[i+1][j] == '1':
                graf[i*m+j].append((i+1)*m+j)
                graf[(i+1)*m+j].append(i*m+j)
            if matrix[i][j] == '1' and matrix[i][j+1] == '1':
                graf[i*m+j].append(i*m+j+1)
                graf[i*m+j+1].append(i*m+j)
    for i in range(n-1):
        if matrix[i][m-1] == '1' and matrix[i+1][m-1] == '1':
            graf[i*m+m-1].append((i+1)*m+m-1)
            graf[(i+1)*m+m-1].append(i*m+m-1)
    for j in range(m-1):
        if matrix[n-1][j] == '1' and matrix[n-1][j+1] == '1':
            graf[(n-1)*m+j].append((n-1)*m+j+1)
            graf[(n-1)*m+j+1].append((n-1)*m+j)

    for i in range(n*m):
        if not seen[i] and len(graf[i]) > 0:
            ElvagoEl(i, 0);

    print s