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)

ss=gets.strip.split('')
sq = ss.join('').squeeze

def rle s
  s.each_char.inject([]) do |memo, c| 
     memo.last && c == memo.last.last ? memo.last[0] += 1 : memo << [1, c]
     memo
  end
end

def summ(n)
  (0..n).to_a.inject(:+)
end


rl = rle(ss.join(''))

result=0

if rl.first.last=='>'
  result += summ(rl.first.first)
  rl.shift
end

if rl.length > 0 && rl.last.last=='<'
  result += summ(rl.last.first)
  rl.pop
end

#p rl
rl.map(&:first).each_slice(2){|l,r|
  ll,rr = [l, r].minmax
  result += (summ(ll-1) + summ(rr))
}

p result