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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
fscanf(STDIN, "%s", $s);
$n = strlen($s);
$a = array_fill(0, $n+1, 0);
for($i = 0; $i < $n; $i++) {
    if($s[$i] === "<") {
        $a[$i+1] = max($a[$i+1], $a[$i]+1);
    }
}

for($i = $n-1; $i > 0; $i--) {
    if($s[$i] === ">") {
        $a[$i] = max($a[$i], $a[$i+1]+1);
    }
}

$ans = array_sum($a);
echo $ans;