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 (3.8.2) (judge verdict: Accepted)

s = input()
count = 1; memo = 0; x = 0
for i in range(1, len(s)):
    if s[i-1] == "<" and s[i] == ">":
        x += count*(count-1)//2
        memo = count
        count = 1
    elif s[i-1] == ">" and s[i] == "<":
        x += count*(count-1)//2+max(count, memo)
        memo = 0
        count = 1
    else:
        count += 1
else:
    if s[-1] == "<":
        x += count*(count+1)//2
    else:
        x += count*(count-1)//2+max(count, memo)
print(x)