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: Accepted)

use std::io;
fn main() {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    let len: usize = s.len() + 1;
    let ch = s.chars().collect::<Vec<char>>();
    let mut left = vec![0; len];
    let mut count_left: u64 = 0;
    let mut count_right: u64 = 0;
    for i in 1..len {
        if ch[i - 1] == '<' {
            count_left += 1;
        } else {
            count_left = 0;
        }
        left[i] = count_left;
    }
    for i in (0..len - 1).rev() {
        if ch[i] == '>' {
            count_right += 1;
        } else {
            count_right = 0;
        }
        left[i] = std::cmp::max(left[i], count_right);
    }
    let ans: u64 = left.into_iter().sum();
    println!("{}", ans);
}