from collections import deque
while True:
    tmp = input().split(" ")
    w = int(tmp[0])
    h = int(tmp[1])
    if w == 0:
        break

    yoko_wall = []
    tate_wall = []

    for i in range(2*h-1):
        if i%2 == 0:
            omega = []
            for k in input().split(" ")[1:]:
                omega.append(int(k))
            yoko_wall.append(omega)
            #縦向きの壁の事
        else:
            omega2 = []
            for r in input().split(" "):
                omega2.append(int(r))
            tate_wall.append(omega2)

    #print("yoko_wall")
    #print(yoko_wall)
    #print("tate")
    #print(tate_wall)

    map_count = []
    for i in range(h):
        tmp = []
        for j in range(w):
            tmp.append(1000)
        map_count.append(tmp)

    q = deque([])
    q.append([0,0])
    map_count[0][0] = 0

    #tans
    while True:
        if len(q) == 0:
            print("0")
            break

        start = q.popleft()

        if start[0] == h-1 and start[1] == w-1:
            print(str(map_count[h-1][w-1]+1))
            break

        #4houkounoidou
        ue = [start[0]-1,start[1]]
        sita = [start[0]+1,start[1]]
        migi = [start[0],start[1]+1]
        hidari = [start[0],start[1]-1]

        #print("where to start" + str(start[0]) + ", " + str(start[1]))

        if ue[0] >= 0 and ue[0] < h and ue[1] >= 0 and ue[1] < w:
            #print("ue")
            #print(ue[0])
            #print(ue[1])
            if tate_wall[ue[0]][ue[1]] == 0:
                if map_count[ue[0]][ue[1]] == 1000:
                    map_count[ue[0]][ue[1]] = map_count[start[0]][start[1]] + 1
                    q.append(ue)
                    #print("new pattern ue")
                #else:
                    #print("already been there")

        if sita[0] >= 0 and sita[0] < h and sita[1] >= 0 and sita[1] < w:
            #print("sita")
            #print(sita[0])
            #print(sita[1])
            if tate_wall[start[0]][start[1]] == 0:
                #print("sita1")
                if map_count[sita[0]][sita[1]] == 1000:
                    #print("sita2")
                    map_count[sita[0]][sita[1]] = map_count[start[0]][start[1]] + 1
                    q.append(sita)
                    #print("new pattern sita")


        if migi[0] >= 0 and migi[0] < h and migi[1] >= 0 and migi[1] < w:
            #print("migi")
            #print(migi[0])
            #print(migi[1])
            if yoko_wall[start[0]][start[1]] == 0:
                if map_count[migi[0]][migi[1]] == 1000:
                    map_count[migi[0]][migi[1]] = map_count[start[0]][start[1]] + 1
                    q.append(migi)
                    #print("new pattern migi")
        #    else:
            #    print("couldnt go migi")

        if hidari[0] >= 0 and hidari[0] < h and hidari[1] >= 0 and hidari[1] < w:
            #print("hidari")
            #print(hidari[0])
            #print(hidari[1])
            if yoko_wall[hidari[0]][hidari[1]] == 0:
                if map_count[hidari[0]][hidari[1]] == 1000:
                    map_count[hidari[0]][hidari[1]] = map_count[start[0]][start[1]] + 1
                    q.append(hidari)



Measured memory_bytes: 6032