n,v = map(int,input().split())
C = list(map(int,input().split()))

cost = []
now = 0
mi = 10**20
mnum = 0
mcost = 0
for i,c in enumerate(C,1):
    now += c
    cost.append([now/i,now])
    if mi > now/i:
        mi = min(mi,now/i)
        mnum = i
        mcost= now
base = 0

base += sum(C)
v -= min(v,n)
took = max(0,(v-100)//mnum)
base += took*mcost
v -= took*mnum

inf = 10**20
dp = [inf]*(v+1)
dp[0] = 0
for i in range(1,n+1):
    c = cost[i-1][1]
    for j in range(v):
        if dp[j] == inf:
            continue
        if j + i <= v:
            dp[j+i] = min(dp[j+i],dp[j]+c)

print(base+dp[-1])