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::cmp::max;
use std::io::prelude::*;
use std::io::stdin;
use std::str::FromStr;

fn main() {
    let s = read::<String>().as_bytes().to_vec();

    let mut dp = vec![0u64; s.len() + 1];

    for (i, c) in s.iter().enumerate() {
        if *c == b'<' {
            dp[i + 1] = max(dp[i + 1], dp[i] + 1);
        }
    }

    for (i, c) in s.iter().enumerate().rev() {
        if *c == b'>' {
            dp[i] = max(dp[i], dp[i + 1] + 1);
        }
    }

    println!("{}", dp.iter().sum::<u64>());
}

#[allow(dead_code)]
fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let token: String = stdin
        .lock()
        .bytes()
        .map(|b| b.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().unwrap()
}