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: Wrong Answer)

def max(a,b); a > b ? a : b; end
S = gets.chomp; N = S.size + 1
L = Array.new(N, 0)
R = Array.new(N, 0)
(1 .. N).each do |i|
  L[i] = (S[i] == '<' ? L[i - 1] + 1 : 0)
  R[N - 1 - i] = (S[N - i] == '>' ? R[N - i] + 1 : 0)
end
ans = N.times.inject(0) do |sum, i|
  sum += max(L[i],R[i])
end
puts ans