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)

def rle(t):
    tmp2, count_, ans_ = t[0], 1, []
    for i_ in range(1, len(t)):
        if tmp2 == t[i_]:
            count_ += 1
        else:
            ans_.append([tmp2, count_])
            tmp2 = t[i_]
            count_ = 1
    ans_.append([tmp2, count_])
    return ans_


S = list(input())

l = rle(S)
ans = [0] * (len(S) + 1)
count = 0
for i in range(len(l)):
    if l[i][0] == '<':
        for j in range(l[i][1] + 1):
            ans[count + j] = max(ans[count + j], j)
    elif l[i][0] == '>':
        for k in range(l[i][1] + 1):
            ans[count + k] = max(ans[count + k], l[i][1] - k)
    count += l[i][1]
print(sum(ans))