Problem:
Score : 300 points

Problem Statement

Given is a string S of length N-1.
Each character in S is < or >.

A sequence of N non-negative integers, a_1,a_2,\cdots,a_N, is said to be good when the following condition is satisfied for all i (1 \leq i \leq N-1):

If S_i= <: a_i<a_{i+1}

If S_i= >: a_i>a_{i+1}

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Constraints

2 \leq N \leq 5 \times 10^5

S is a string of length N-1 consisting of < and >.

Input

Input is given from Standard Input in the following format:

S

Output

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Sample Input 1

<>>

Sample Output 1

3

a=(0,2,1,0) is a good sequence whose sum is 3.
There is no good sequence whose sum is less than 3.

Sample Input 2

<>>><<><<<<<>>><

Sample Output 2

28

Solution in Ruby (2.7.1) (judge verdict: Accepted)

s = gets.chomp
n = s.length

l_ar = Array.new(n+1, 0)
r_ar = Array.new(n+1, 0)

l_sum = 0
n.times do |i|
  if s[i] == '<'
    l_sum += 1
  else
    l_sum = 0
  end
  l_ar[i+1] = l_sum
end

r_sum = 0
(n-1).downto(0) do |i|
  if s[i] == '>'
    r_sum += 1
  else
    r_sum = 0
  end
  r_ar[i] = r_sum
end

sum = 0
(n+1).times do |i|
  sum += [l_ar[i], r_ar[i]].max
end

puts sum