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)

str = gets.chomp.split('')
t = 0
l_t = [0]
str.each do |s| 
    if s == '<'
        t += 1
    else
        t = 0
    end
    l_t << t
end
t = 0
r_t = [0]
str.reverse.each do |s|
    if s == '>'
        t += 1
    else
        t = 0
    end
    r_t.unshift(t)
end
ans = 0
0.upto(str.size) do |i|
    
    ans += [l_t[i], r_t[i]].max
end

puts ans