N, M = gets.split.map(&:to_i)
L = gets.split.map(&:to_i)
lake = L.tally
L << Float::INFINITY
Q = M.times.map { gets.split.map(&:to_i) }

ans = 0

Q.each do |f, b, w|
  idx = L.bsearch_index { |l| l >= f }

  if lake[f]
    ans += w
  else
    cur_power = b

    if L[idx] != Float::INFINITY
      d = L[idx] - f

      if cur_power < w - d 
        cur_power = w - d
      end
    end

    if idx - 1 >= 0
      d = f - L[idx - 1]

      if cur_power < w - d
        cur_power = w - d
      end
    end

    ans += cur_power
  end
end

puts ans