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 (2.7.1) (judge verdict: Accepted)

s=gets.chomp

n=s.length+1
count_l=Array.new(n,0)
count_r=Array.new(n,0)

count=0
(n-1).times do |i|
    if s[i]=="<"
        count+=1
    else
        count=0
    end
    count_l[i+1]=count
end

count=0
(n-2).downto(0) do |i|
    if s[i]==">"
        count+=1
    else
        count=0
    end
    count_r[i]=count
end

ans=0
n.times do |i|
    ans+=[count_l[i],count_r[i]].max
end
puts ans