n, m = gets.split.map(&:to_i)
ws = gets.split.map(&:to_i)
memo = Array.new(2){ Array.new(2){ Array.new(m+1, -Float::INFINITY) } }

memo[0][0][m] = 0
memo[1][1][m-1] = 0
0.upto(n-2){|i|
	0.upto(m){|j|
		memo[0][0][j] = memo[0][0][j] > memo[0][1][j] ? memo[0][0][j] : memo[0][1][j]
		memo[0][1][j] = memo[0][0][j+1] > memo[0][1][j+1] + ws[i] ? memo[0][0][j+1] : memo[0][1][j+1] + ws[i] if j < m
		memo[1][0][j] = memo[1][0][j] > memo[1][1][j] ? memo[1][0][j] : memo[1][1][j]
		memo[1][1][j] = memo[1][0][j+1] > memo[1][1][j+1] + ws[i] ? memo[1][0][j+1] : memo[1][1][j+1] + ws[i] if j < m
	}
}

memo[1][1][0] += ws.last
puts [memo[0][0][0], memo[0][1][0], memo[1][0][0], memo[1][1][0]].max