N, K = list(map(int, input().strip().split()))

AList = list(map(int, input().strip().split()))



length = len(AList ) - 1

ans = 0

while(length > 0):

    ans += 1

    length = length - (K - 1)

print(ans)
N, K = list(map(int, input().strip().split()))

print((int((N- 1) / (K - 1)) + (0 if (N-1)%(K-1)==0 else 1)))
N, K = list(map(int, input().strip().split()))
AList = list(map(int, input().strip().split()))
length = len(AList) - 1
ans = 0
while length > 0:
    ans += 1
    length = length - (K - 1)
print(ans)

N, K = list(map(int, input().strip().split()))
print((int((N - 1) / (K - 1)) + (0 if (N - 1) % (K - 1) == 0 else 1)))

-AList = list(map(int, input().strip().split())) -length = len(AList) - 1 -ans = 0 -while length > 0: -    ans += 1 -    length = length - (K - 1) -print(ans) +print((int((N - 1) / (K - 1)) + (0 if (N - 1) % (K - 1) == 0 else 1)))