N, K = [int(_) for _ in input().split()]
P = [int(_) for _ in input().split()]

ans = 0.0
k = 0
v = 0.0
for i in range(N):
    v += (P[i] + 1) / 2
    k += 1
    if k > K:
        v -= (P[i-K] + 1) / 2
        k -= 1
    ans = max(ans, v)
print(ans) int(_) for _ in input().split() for _ in input().split() _ input().split() ().split () input split for _ in input().split() int(_) int _ N, K = [int(_) for _ in input().split()] N [int(_) for _ in input().split()] K int(_) for _ in input().split() for _ in input().split() _ input().split() ().split () input split for _ in input().split() int(_) int _ P = [int(_) for _ in input().split()] P [int(_) for _ in input().split()] ans = 0.0 ans 0.0 k = 0 k 0 v = 0.0 v 0.0 for i in range(N):
    v += (P[i] + 1) / 2
    k += 1
    if k > K:
        v -= (P[i-K] + 1) / 2
        k -= 1
    ans = max(ans, v) i range(N) range N v += (P[i] + 1) / 2 v (P[i] + 1) / 2 P[i] + 1 P[i] P i 1 2 k += 1 k 1 if k > K:
        v -= (P[i-K] + 1) / 2
        k -= 1
     k > K k K v -= (P[i-K] + 1) / 2 v (P[i-K] + 1) / 2 P[i-K] + 1 P[i-K] P i-K i K 1 2 k -= 1 k 1 ans = max(ans, v) ans max(ans, v) max ans v print(ans) print ans P = [int(_) for _ in input().split()] [int(_) for _ in input().split()] P v += (P[i] + 1) / 2 (P[i] + 1) / 2 v k += 1 1 k v -= (P[i-K] + 1) / 2 (P[i-K] + 1) / 2 v ans = max(ans, v) max(ans, v) ans v = 0.0 0.0 v ans = 0.0 0.0 ans k -= 1 1 k N, K = [int(_) for _ in input().split()] [int(_) for _ in input().split()] N k = 0 0 k K = [int(_) for _ in input().split()] [int(_) for _ in input().split()] K
N, K = [int(_) for _ in input().split()]
P = [int(_) for _ in input().split()]

ans = 0.0
k = 0
v = 0.0
for i in range(N):
    v += (P[i] + 1) / 2
    k += 1
    if k > K:
        v -= (P[i-K] + 1) / 2
        k -= 1
    ans = max(ans, v)
print(ans)
