BOJ 2343

[Merrychristmasyo]

n, m = map(int,input().split())
time = list(map(int,input().split()))

start = max(time)
end = sum(time)

while start <= end:
mid = (start + end) // 2

total = 0
count = 1
for t in time:
    if total + t > mid:
        count += 1
        total = 0
    total += t 

if count <= m:
    ans = mid
    end = mid - 1
else:
    start = mid + 1

print(ans)