N, K = [int(x) for x in input().split()]
p = [int(x) for x in input().split()]

a = sum(p[:K])
s = sum(p[:K])
for i in range(K, N):
    s += p[i] - p[i - K]
    a = max(a, s)

ans = (a + K) / 2
print(ans) int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x N, K = [int(x) for x in input().split()] N [int(x) for x in input().split()] K int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x p = [int(x) for x in input().split()] p [int(x) for x in input().split()] a = sum(p[:K]) a sum(p[:K]) sum p[:K] p :K K s = sum(p[:K]) s sum(p[:K]) sum p[:K] p :K K for i in range(K, N):
    s += p[i] - p[i - K]
    a = max(a, s) i range(K, N) range K N s += p[i] - p[i - K] s p[i] - p[i - K] p[i] p i p[i - K] p i - K i K a = max(a, s) a max(a, s) max a s ans = (a + K) / 2 ans (a + K) / 2 a + K a K 2 print(ans) print ans K = [int(x) for x in input().split()] [int(x) for x in input().split()] K a = max(a, s) max(a, s) a p = [int(x) for x in input().split()] [int(x) for x in input().split()] p a = sum(p[:K]) sum(p[:K]) a s = sum(p[:K]) sum(p[:K]) s N, K = [int(x) for x in input().split()] [int(x) for x in input().split()] N s += p[i] - p[i - K] p[i] - p[i - K] s ans = (a + K) / 2 (a + K) / 2 ans
N, K = [int(x) for x in input().split()]
p = [int(x) for x in input().split()]

a = sum(p[:K])
s = sum(p[:K])
for i in range(K, N):
    s += p[i] - p[i - K]
    a = max(a, s)

ans = (a + K) / 2
print(ans)