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 (2.3.3) (judge verdict: Accepted)

S = gets.chomp!

lefts = Array.new(S.size + 1, 0)
S.each_char.with_index do |c, i|
  if c == '<'
    lefts[i+1] = lefts[i] + 1
  end
end

rights = Array.new(S.size + 1, 0)

S.each_char.reverse_each.with_index do |c, i|
  if c == '>'
    rights[i+1] = rights[i] + 1
  end
end

rights.reverse!
ans = 0
(S.size + 1).times do |i|
  ans += [lefts[i], rights[i]].max
end

puts ans