#![allow(unused_parens)]
#![allow(unused_imports)]
#![allow(non_upper_case_globals)]

#[allow(unused_macros)]
macro_rules! invec {
    ( $ t : ty ) => {{
        let mut s = String::new();
        match std::io::stdin().read_line(&mut s) {
            Ok(0) => Vec::<$t>::new(),
            Ok(n) => s
                .trim()
                .split_whitespace()
                .map(|s| s.parse::<$t>().unwrap())
                .collect::<Vec<$t>>(),
            Err(_) => Vec::<$t>::new(),
        }
    }};
}

#[allow(unused_macros)]
macro_rules! get {
      ($t:ty) => {
          {
              let mut line: String = String::new();
              std::io::stdin().read_line(&mut line).unwrap();
              line.trim().parse::<$t>().unwrap()
          }
      };
      ($($t:ty),*) => {
          {
              let mut line: String = String::new();
              std::io::stdin().read_line(&mut line).unwrap();
              let mut iter = line.split_whitespace();
              (
                  $(iter.next().unwrap().parse::<$t>().unwrap(),)*
              )
          }
      };
      ($t:ty; $n:expr) => {
          (0..$n).map(|_|
              get!($t)
          ).collect::<Vec<_>>()
      };
      ($($t:ty),*; $n:expr) => {
          (0..$n).map(|_|
              get!($($t),*)
          ).collect::<Vec<_>>()
      };
      ($t:ty ;;) => {
          {
              let mut line: String = String::new();
              std::io::stdin().read_line(&mut line).unwrap();
              line.split_whitespace()
                  .map(|t| t.parse::<$t>().unwrap())
                  .collect::<Vec<_>>()
          }
      };
      ($t:ty ;; $n:expr) => {
          (0..$n).map(|_| get!($t ;;)).collect::<Vec<_>>()
      };
}

#[allow(unused_macros)]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let mut s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};

    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
    ($iter:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };

    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };

    ($next:expr, [$t:tt]) => {
        {
            let len = read_value!($next, usize);
            (0..len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
        }
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };

    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };

    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

#[cfg(debug_assertions)]
macro_rules! mydbg {
    //($arg:expr) => (dbg!($arg))
    //($arg:expr) => (println!("{:?}",$arg));
      ($($a:expr),*) => {
          eprintln!(concat!($(stringify!($a), " = {:?}, "),*), $($a),*);
      }
}
#[cfg(not(debug_assertions))]
macro_rules! mydbg {
    ($($arg:expr),*) => {};
}

macro_rules! echo {
    ($($a:expr),*) => {
          $(println!("{}",$a))*
      }
}

struct SliceDisplay<'a, T: 'a>(&'a [T]);
impl<'a, T: std::fmt::Display + 'a> std::fmt::Display for SliceDisplay<'a, T> {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        for item in self.0 {
            write!(f, "{} ", item)?;
        }
        Ok(())
    }
}

use std::cmp::*;
use std::collections::*;
use std::ops::{Add, Div, Mul, Sub};

#[allow(dead_code)]
static INF_I64: i64 = 92233720368547758;
#[allow(dead_code)]
static INF_I32: i32 = 21474836;
#[allow(dead_code)]
static INF_USIZE: usize = 18446744073709551;
#[allow(dead_code)]
static M_O_D: usize = 1000000007;

fn c1(s: &Vec<char>, cur: &mut usize) -> bool {
    if s[*cur] == 'd'
        && *cur + 4 < s.len()
        && s[*cur + 1] == 'r'
        && s[*cur + 2] == 'e'
        && s[*cur + 3] == 'a'
        && s[*cur + 4] == 'm'
    {
        *cur += 5;
        return true;
    }
    return false;
}
fn c2(s: &Vec<char>, cur: &mut usize) -> bool {
    if s[*cur] == 'e' && *cur + 1 < s.len() && s[*cur + 1] == 'r' {
        *cur += 2;
        return true;
    }
    return false;
}
fn c3(s: &Vec<char>, cur: &mut usize) -> bool {
    if s[*cur] == 'e'
        && *cur + 4 < s.len()
        && s[*cur + 1] == 'r'
        && s[*cur + 2] == 'a'
        && s[*cur + 3] == 's'
        && s[*cur + 4] == 'e'
    {
        *cur += 5;
        return true;
    }
    return false;
}
fn c4(s: &Vec<char>, cur: &mut usize) -> bool {
    if s[*cur] == 'e'
        && *cur + 5 < s.len()
        && s[*cur + 1] == 'r'
        && s[*cur + 2] == 'a'
        && s[*cur + 3] == 's'
        && s[*cur + 4] == 'e'
        && s[*cur + 5] == 'r'
    {
        *cur += 6;
        return true;
    }
    return false;
}

fn main() {
    input! {
       s:chars,
    }

    let mut ans: usize = 0;
    let mut cur = 0;
    while cur < s.len() {
        if c1(&s, &mut cur) {
            if cur == s.len() {
                break;
            }
            if c4(&s, &mut cur) {
                continue;
            } else if c3(&s, &mut cur) {
                continue;
            } else if c2(&s, &mut cur) {
                continue;
            }
        } else if c4(&s, &mut cur) {
            continue;
        } else if c3(&s, &mut cur) {
            continue;
        } else {
            echo!("NO");
            return;
        }
    }

    echo!("YES");
}


Measured memory_bytes: 4352