#![allow(dead_code, unused_imports, unused_macros, non_snake_case)]

fn main() {
    input! {
        S: Chars,
    }

    let mut ans = S.len();
    let mut prev_lteq = vec![];
    for c in S {
        if c == '<' {
            prev_lteq.push(1);
        } else if c == '=' {
            if let Some(n) = prev_lteq.last_mut() {
                *n += 1;
            }
        } else if c == '>' {
            if let Some(n) = prev_lteq.pop() {
                if n <= 1 {
                    prev_lteq.clear();
                } else {
                    ans -= n + 1;
                }
            }
        }
    }

    println!("{ans}");
}

type Int = i64;
const MOD: Int = 1_000_000_007;
const INF: Int = 1_000_000_000;
const YESNO: [&'static str; 2] = ["Yes", "No"];

use proconio::{input, marker::{Usize1, Chars}};

fn yes() { println!("{}", YESNO[0]); }
fn no() { println!("{}", YESNO[1]); }
fn yesno(c: bool) { println!("{}", if c { YESNO[0] } else { YESNO[1] }); }