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)

L = input()
L = list(L.split('><'))
if len(L) == 1:
    a = [L[0].count('<'),L[0].count('>')]
    a_max = max(a)
    ans = a_max*(a_max+1)/2
else:
    ans = 0
    for i in range(len(L)):
        if i == 0:
            a = [L[i].count('<'),L[i].count('>')+1]
        elif i == len(L)-1:
            a = [L[i].count('<')+1,L[i].count('>')]
        else:
            a = [L[i].count('<')+1,L[i].count('>')+1]
        a_max = max(a)
        a_min = min(a)

        ans += a_max*(a_max+1)/2
        ans += a_min*(a_min-1)/2

print(int(ans))