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)

from collections import deque
S = input()
left = deque([0])
right = deque([0])
cnt = 0
for s in S:
    if s == '<':
        cnt += 1
    else:
        cnt = 0
    left.append(cnt)
cnt = 0
for s in S[::-1]:
    if s == '>':
        cnt += 1
    else:
        cnt = 0
    right.appendleft(cnt)
ans = 0
for l, r in zip(left, right):
    ans += max(l, r)
print(ans)