function main(input) {
  const reverse = (s) => {
    return s.split("").reverse().join("");
  };

  const WORDS = ["dream", "dreamer", "erase", "eraser"].map(reverse);
  const S = reverse(input.split("\n")[0]);

  var index = 0;

  while (true) {
    var w = WORDS.find((w) => S.startsWith(w, index));
    if (!w) break;
    index += w.length;
  }

  if (S.length === index) {
    console.log("YES");
  } else {
    console.log("NO");
  }
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));
