# Here your code !
# 1 + 3 + 5 + ... = N * (1 + (2N-1))/2 = N * N

N = gets.to_i
A = gets.split.map(&:to_i)
sum = A.inject(&:+)
level = Math.sqrt(sum).floor
#level = [level,(N+1)/2].min
mintotal = 1000000
#puts "sum=#{sum}, level=#{level}"
# (0+(level-1)...N-(level-1)).each{|i|
(level-1..level-1).each{|i|
    total = 0
    #puts "i=#{i}"
    # (-(level-1)..(level-1)).each{|j|
    (0...N).each{|j|
        h = 0
        if j>=0 && j< N then
            h = A[j]
        end
        base = 0 
        if level >= (i-j).abs
             base = level - (i-j).abs 
        end
        if h > base then
            diff = (h - base).abs
            total += diff
        end
        #puts "i=#{i}, j=#{j}, h=#{h}, base=#{base}, diff=#{diff}, total=#{total}"
    }
    mintotal = [mintotal, total].min
}
puts mintotal