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: Wrong Answer)

s = input()
total = 0
if s[0] == '<':
    status = 'pos'
    v = 0
    c_neg = 0
else:
    status = 'neg'
    c_neg = 1
    v = 0
i = 1
while i < len(s):
    if s[i] == '<':
        if status == 'neg':
            total += int(c_neg*(c_neg+1))/2
            total -= min(v,c_neg)
            #c_neg = 0
            v = 1
            total += v
            status = 'pos'
        else:
            v += 1
            total += v
    else:
        if status == 'pos':
            #total -= v
            status = 'neg'
            c_neg = 1
        else:
            c_neg += 1
    i += 1
#終了処理
if status == 'neg':
    total += int(c_neg*(c_neg+1))/2
    total -= min(v,c_neg)
            
if len(s) == 1:
    total = 1
print(int(total))