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 = input()

nums = []

cnt = 1
pre = S[0]

for i in range(1, len(S)):
    if pre != S[i]:
        nums.append(cnt)
        pre = S[i]
        cnt = 1
    else:
        cnt += 1

nums.append(cnt)

def cal_sum(n):
    return n * (n + 1) // 2


if S[0] == '>':
    nums = [0] + nums
if S[-1] == '<':
    nums = nums + [0]

ans = 0
for i in range(len(nums) // 2):
    max_ = max(nums[2 * i], nums[2 * i+1])
    min_ = min(nums[2 * i], nums[2 * i+1])
    ans += cal_sum(max_)
    ans += cal_sum(min_ - 1)

print(ans)