from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    R, C = map(int, input().split())
    SY, SX = map(int, input().split())
    GY, GX = map(int, input().split())
    C_ = stdin.read().splitlines()

    print(abs(GY - SY) + abs(GX - SX))


main()