'use strict'
const main = arg => {
	const input = arg.trim().split("\n");
	let s = input[0]
	const parts = ['dream', 'dreamer', 'erase', 'eraser']
	const replaced = []
	let failure = 0
	let sameCount = 0
	//replaceを続け、replaceできなくなったら一つ戻る
	while(1) {
		for(let i = 0 ; i < parts.length ; i++) {
			
			let before = s
			s = s.replace(new RegExp('^' + parts[i]), '')
			if(s === '') {
				console.log('YES')
				return
			}
			if(s === before) {
				sameCount++
			} else {
				sameCount = 0
				failure = 0
				replaced.push({moji: parts[i], idx: i})
			}
			if(sameCount >= parts.length - 1) {
				failure++
				// １つ前の選択肢を戻す
				s = replaced[replaced.length - 1].moji + s
				i = replaced[replaced.length - 1].idx
			}
			if(failure >= parts.length) {
				console.log('NO')
				return
			}
		}
	}
}   
main(require('fs').readFileSync('/dev/stdin', 'utf8'));