import sys
for n in "XYL":
    exec(f"{n} = int(input())")

comm = 0

if X == 0:
    if Y == 0:
        print(comm)
        sys.exit()
    elif Y > 0:
        comm = 0
    else:
        comm += 2
else:
    if Y == 0:
        comm += 1
    else:
        comm += 2
        
x,mx = divmod(X,L); x += 1 if mx > 0 else x
y,my = divmod(Y,L); y += 1 if yx > 0 else y
comm = comm + x + y

print(comm)