def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    K = int(input[idx])
    idx += 1
    A = list(map(int, input[idx:idx+N]))
    
    if K == 0:
        print(0)
        return
    
    total = sum(A)
    if K == 1:
        print(total)
        return
    
    low = 0
    high = total
    best = 0
    
    def is_possible(mid):
        if mid * K > total:
            return False
        B = A + A
        prefix = [0] * (2 * N + 1)
        for i in range(2 * N):
            prefix[i + 1] = prefix[i] + B[i]
        
        for i in range(N):
            end = i + N
            total_sub = prefix[end] - prefix[i]
            if total_sub < mid * K:
                continue
            
            cnt = 0
            current_sum = 0
            for j in range(i, i + N):
                current_sum += B[j]
                if current_sum >= mid:
                    cnt += 1
                    current_sum = 0
                    if cnt >= K:
                        break
            if cnt >= K:
                return True
        return False
    
    while low <= high:
        mid = (low + high) // 2
        if is_possible(mid):
            best = mid
            low = mid + 1
        else:
            high = mid - 1
    print(best)

if __name__ == "__main__":
    main()