/// Rustで競技プログラミングの入力をスッキリ記述するマクロ
///
/// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

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

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

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

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

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

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

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

#[inline]
#[allow(dead_code)]
fn gcd(mut m: u64, mut n: u64) -> u64 {
    if m < n {
        std::mem::swap(&mut m, &mut n);
    }

    loop {
        let k = m % n;
        if k == 0 {
            return n;
        }

        m = n;
        n = k;
    }
}

#[inline]
#[allow(dead_code)]
fn lcm(m: u64, n: u64) -> u64 {
    m / gcd(m, n) * n
}

macro_rules! eprint(
    ($($arg:tt)*) => { {
        use std::io::Write;
        let r = write!(&mut ::std::io::stderr(), $($arg)*);
        r.expect("failed printing to stderr");
    } }
);

macro_rules! eprintln(
    ($($arg:tt)*) => { {
        use std::io::Write;
        let r = writeln!(&mut ::std::io::stderr(), $($arg)*);
        r.expect("failed printing to stderr");
    } }
);

macro_rules! dbg {
    ($val:expr) => {
        // Use of `match` here is intentional because it affects the lifetimes
        // of temporaries - https://stackoverflow.com/a/48732525/1063961
        match $val {
            tmp => {
                eprintln!("[{}:{}] {} = {:#?}",
                          file!(), line!(), stringify!($val), &tmp);
                tmp
            }
        }
    }
}

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

    let mut i = 0usize;
    let mut q = 0;

    while i < s.len() {
        if q == 0 {
            if i+5 <= s.len() && &s[i..i+5] == "dream" {
                i += 5;
                q = 1;
            } else if i+5 <= s.len() && &s[i..i+5] == "erase" {
                i += 5;
                q = 2;
            } else {
                println!("NO");
                return;
            }
        } else if q == 1 {
            if i+5 <= s.len() && &s[i..i+5] == "dream" {
                i += 5;
                q = 1;
            } else if i+5 <= s.len() && &s[i..i+5] == "erase" {
                i += 5;
                q = 2;
            } else if i+2 <= s.len() && &s[i..i+2] == "er" {
                i += 2;
                q = 0;
            } else {
                println!("NO");
                return;
            }
        } else if q == 2 {
            if i+5 <= s.len() && &s[i..i+5] == "dream" {
                i += 5;
                q = 1;
            } else if i+5 <= s.len() && &s[i..i+5] == "erase" {
                i += 5;
                q = 2;
            } else if i+1 <= s.len() && &s[i..i+1] == "r" {
                i += 1;
                q = 0;
            } else {
                println!("NO");
                return;
            }
        }
    }

    println!("YES");
}


Measured memory_bytes: 4352