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

if K > (N + 1) // 2:
    print("Impossible")
    exit()

dp0 = [-1 << 60] * (K + 1)
dp1 = [-1 << 60] * (K + 1)
dp0[0] = 0
for a in A:
    ndp0 = [-1 << 60] * (K + 1)
    ndp1 = [-1 << 60] * (K + 1)
    for k in range(K + 1):
        ndp0[k] = max(dp0[k], dp1[k])
        if k < K:
            ndp1[k + 1] = dp0[k] + a
    dp0, dp1 = ndp0, ndp1
print(max(dp0[K], dp1[K]))