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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
$s = trim(fgets(STDIN));
$cs = str_split($s);
$res = 0;
$prev = '';
$i=0;
$tmp=0;
foreach ($cs as $c) {
  $i++;
  if ($prev != '' && $c != $prev) {
    if ($c == '>') {
      $tmp = $i - 1;
    } else {
      if ($tmp) {
        if ($tmp < $i - 1) {
          $res -= $tmp;
        } else {
          $res -= $i - 1;
        }
        $tmp = 0;
      }
    }
    $i = 1;
  }
  $res += $i;
  $prev = $c;
}
if ($tmp) {
  if ($tmp < $i - 1) {
    $res -= $tmp;
  } else {
    $res -= $i - 1;
  }
}
echo $res;