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.chars
n = s.size

ans = [0]*(n+1)

i = 0
while i < n
  if s[i] == '<'
    while i < n && s[i] == '<' # 右にある<を数える
      ans[i+1] = ans[i] + 1
      i += 1
    end
  else
    i += 1
  end
end

i = n-1
while i >= 0
  if s[i] == '>'
    while i >= 0 && s[i] == '>'
      ans[i] = [ans[i+1] + 1, ans[i]].max
      i -= 1
    end
  else
    i -= 1
  end
end

print ans.inject(:+)