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

cost = []
now = 0

mnum = 0
mcost = 0
for i,c in enumerate(C,1):
    now += c
    cost.append(now)
    if mnum == 0:
        mnum = i
        mcost = now
        continue

    if mcost*i > now*mnum:
        mnum = i
        mcost = now

base = sum(C)
v -= min(v,n)
took = max(0,(v-2000)//mnum)
base += took*mcost
v -= took*mnum

inf = 10**30
dp = [inf]*(v+1)
dp[0] = 0
for i, c in enumerate(cost,1):
    for j in range(v+1):
        if dp[j] == inf:
            continue
        if j + i <= v:
            dp[j+i] = min(dp[j+i],dp[j]+c)

print(base+dp[-1])