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 Rust (1.15.1) (judge verdict: Wrong Answer)

use std::io::stdin;
use std::cmp::max;

fn main() {
    let mut s: Vec<char> = {
        let mut s = String::new();
        stdin().read_line(&mut s).unwrap();
        s.trim_right().to_owned().chars().collect()
    };
    let mut nums = vec![0_i32;s.len()+1];

    //  s0, s1, s2, ....   sm
    // n0, n1, n2,.....nm-1, nm

    let mut prev = s[0];
    let mut cnt = 0;
    for i in 1..(s.len()) {
        if s[i] == prev {
            cnt+=1;
            continue;
        } else {
            if prev == '>' {
                for j in 0..(cnt+2) {
                    nums[i-j] = max(j as i32, nums[i-j])
                }
            } else {
                for j in 0..(cnt+2) {
                    nums[i-j] = max(((cnt+1)-j) as i32, nums[i-j])
                }
            }
            cnt = 0;
            prev = s[i];
        }
    }
    // はじ
    let last = nums.len() - 1;
    if s[s.len()-1] == '>' {
        for j in 0..(cnt+2) {
            nums[last-j] = max(j as i32, nums[last-j])
        }
    } else {
        for j in 0..(cnt+2) {
            nums[last-j] = max(((cnt+1)-j) as i32, nums[last-j])
        }
    }

    println!("{}", nums.iter().fold(0, |sum, a| sum + *a));
}