use std::io::{self, BufRead};

fn main() {
    io::stdin().lock().lines().for_each(|l| {
        let s = l.unwrap().chars().collect::<Vec<_>>();

        let tt = s.iter().filter(|&&c| c == 't').count();
        let rr = s.iter().filter(|&&c| c == 'r').count();
        let ee = s.iter().filter(|&&c| c == 'e').count();

        let min = tt.min(rr).min(ee / 2);

        println!("{}", min);
    });
}