import sys
sys.setrecursionlimit(10000)
T = 1000
g = []
h = []
for t in range(T):
    n, k = map(int, input().split())
    x = (n-1) % (k+1) != 0
    y = (n-2) % (k+1) != 0
    g.append(x)
    h.append(y)

dp = {}
def calc(f, t):
    if t == T:
        return 0
    if (f, t) in dp:
        return dp[(f, t)]
    res = 0
    if g[t]:
        tmp = (T - (t+1) - calc(not f, t+1)) + 1
        if res < tmp:
            res = tmp
    if h[t]:
        tmp = calc(f, t+1)
        if res < tmp:
            res = tmp

    dp[(f, t)] = res
    return res
        
print(calc(True,0))