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 Python (3.4.3) (judge verdict: Accepted)

s = list(input())

now = '>'
count = 0
nums = []
score = 0

for i in range(len(s)) :
    if s[i] == now :
        count += 1
    else :
        nums.append(count)
        count = 1
        now = s[i]

nums.append(count)

if s[len(s) - 1] == '>' :
    nums.append(0)

for j in range(len(nums)) :
    score += nums[j] * (nums[j] + 1) //2
    if j > 0 and j % 2 == 0 :
        if nums[j - 1] > nums[j] :
            score -= nums[j]
        else :
            score -= nums[j - 1]

print(score)