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()
n = len(s)
a1 = [0] * (n+1) # 左側に連続する<の個数
a2 = [0] * (n+1) # 右側に連続する>の個数
tmp1 = 0
tmp2 = 0
for i in range(n):
    if s[i] == "<": tmp1 += 1
    else: tmp1 = 0
    if s[n-i-1] == ">": tmp2 += 1
    else: tmp2 = 0
    a1[i+1] = tmp1
    a2[n-i-1] = tmp2
ans = 0
for i in range(n+1):
    ans += max(a1[i], a2[i])
print(ans)