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'));
