n,k=map(int,input().split())

A=list(map(int,input().split()))
if k==0:
    print(min(A))
    exit()

min_num=2**61-1
min_ind=[]
for i in range(n):
    if min_num>A[i]:
        min_ind.append(i)
        min_num=A[i]

ans=A[min_ind[-1]]

for j in range(len(min_ind)-1,-1,-1):
    if j==0:
        ans+=k
        break
    n_ind=min_ind[j]
    p_ind=min_ind[j-1]
    
    y=(A[p_ind]-ans)//(n_ind+1)
    if y>=k:
        ans+=k*(n_ind+1)
        break
    k-=y
    ans+=y*(n_ind+1)
    
    if min(ans+n_ind+1,A[p_ind])>=ans+p_ind+1:
        k-=1
        ans=A[p_ind]

print(ans)