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: Accepted)

<?php

fscanf(STDIN, "%s", $str);
$smap = str_split($str);
$last = "";
$lvalue = 0;
$larray = [];
$first = $smap[0];
foreach($smap as $value){
       if($value == $last){
           $lvalue++;
       }else{
           if($lvalue > 0){
               $larray[] = $lvalue;
           }
           $lvalue = 1;
           $last = $value;
       }
}
if($lvalue > 0){
    $larray[] = $lvalue;
}
$ans = 0;
$alast = 0;
if($first == ">"){
    $mode = 1;
}else{
    $mode = 0;
}
foreach($larray as $value){
    if($mode == 0){
        $ans += ($alast + ($alast + $value))* ($value + 1) / 2;
        $alast = ($alast + $value);
        $mode = 1;
    }else{
        if($value > $alast){
            $ans += $value - $alast;
        }
        $ans += ($value - 1) * $value / 2;
        $alast = 0;
        $mode = 0;
    }
}
echo $ans;