#![allow(non_snake_case)]
#![allow(unused_imports)]
#![allow(unused_macros)]
#![allow(clippy::needless_range_loop)]
#![allow(clippy::comparison_chain)]
#![allow(clippy::nonminimal_bool)]
#![allow(clippy::neg_multiply)]
#![allow(dead_code)]
#![allow(clippy::collapsible_else_if)]
use proconio::{
    fastout, input, input_interactive,
    marker::{Chars, Usize1},
};
use std::cmp::Reverse;
use std::collections::BinaryHeap;
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, VecDeque};
use std::mem::swap;

//const MOD: usize = 1e9 as usize + 7;
const MOD: usize = 998244353;
// const MOD: usize = 2147483647;

#[macro_export]
macro_rules! max {
    ($x: expr) => ($x);
    ($x: expr, $( $y: expr ),+) => {
        std::cmp::max($x, max!($( $y ),+))
    }
}
#[macro_export]
macro_rules! min {
    ($x: expr) => ($x);
    ($x: expr, $( $y: expr ),+) => {
        std::cmp::min($x, min!($( $y ),+))
    }
}
fn main() {
    input! {
        S:Chars,
    }
    let mut stk = VecDeque::new();
    let N = S.len();
    for i in 0..N {
        if S[i] == '>' {
            let mut tmp_stk = VecDeque::new();
            tmp_stk.push_back(S[i]);
            while !stk.is_empty() && stk[stk.len() - 1] == '=' {
                tmp_stk.push_back(stk.pop_back().unwrap());
            }
            if !stk.is_empty() && stk[stk.len() - 1] == '<' && tmp_stk.len() >= 2 {
                tmp_stk.push_back(stk.pop_back().unwrap());
            } else {
                while !tmp_stk.is_empty() {
                    stk.push_back(tmp_stk.pop_back().unwrap());
                }
            }
            //eprintln!("{:?}", stk);
        } else {
            stk.push_back(S[i]);
        }
    }
    println!("{}", stk.len());
}