import sys readline=sys.stdin.readline def Bisect_Int(ok,ng,is_ok): while abs(ok-ng)>1: mid=(ok+ng)//2 if is_ok(mid): ok=mid else: ng=mid return ok N,K=map(int,readline().split()) A=list(map(int,readline().split())) sum_A=sum(A) A=[0]+A*2 for i in range(1,2*N+1): A[i]+=A[i-1] def is_ok(ans): perm=[i for i in range(2*N+1)] r=0 for l in range(2*N): while r<2*N and A[r]-A[l]<ans: r+=1 perm[l]=r k=K.bit_length() perm_doub=[[perm[n]] for n in range(2*N+1)] for kk in range(1,k): for n in range(2*N+1): perm_doub[n].append(perm_doub[perm_doub[n][kk-1]][kk-1]) for i in range(N): x=i for kk in range(k): if K>>kk&1: x=perm_doub[x][kk] if ans<A[i]: break if x<=i+N: return True return False ans=Bisect_Int(0,sum_A//K+1,is_ok) print(ans)