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())
n = len(s) + 1
al, ar = [0] * n, [0] * n

for i in range(len(s)):
    if s[i] == "<":
        al[i+1] = al[i] + 1

for i in range(len(s)):
    if s[-(i+1)] == ">":
        ar[i+1] = ar[i] + 1

ans = 0
ar = ar[::-1]

for i in range(len(al)):
    if al[i] >= ar[i]:
        ans += al[i]
    else:
        ans += ar[i]

print(ans)