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

$a = trim(fgets(STDIN));

$count = strlen($a);

if($count ===1){
    echo 1;
    exit;
}

$arr = [];
$j = 1;
for ($i = 0; $i < $count - 1; $i++) {
    if ($a[$i] === $a[$i + 1]) {
        $j++;

    } else {
        $arr[] = $j;
        $j = 1;
    }
}

$arr_count = count($arr);
$ans = $j ===1 && $a[$count-1] !== '<'? 0:array_sum(range(0, $j));
$n = $arr_count % 2 ===0? 0: $arr[0];
$ans += array_sum(range(0, $n));

for ($i = $arr_count % 2 ===0?0:1; $i < $arr_count-1; $i+=2) {
    if($arr[$i] < $arr[$i+1]){
        $ans += array_sum(range(0, $arr[$i] - 1));
        $ans += array_sum(range(0, $arr[$i+1]));
    } else {
        $ans += array_sum(range(0, $arr[$i]));
        $ans += array_sum(range(0, $arr[$i+1] - 1));
    }
}

echo $ans;