#include <bits/stdc++.h>
using namespace std;

#define NDEBUG
#ifdef DEBUG
#include "../cout11.h"
#undef NDEBUG
#endif
#include <cassert>

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;

#define sz(a)  int((a).size())
#define pb  push_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))

#define INTSPACE 12
char _buf[INTSPACE*1000000 + 3];

int loadint() {
    if (fgets(_buf, INTSPACE+3, stdin)==NULL) return 0;
    return atoi(_buf);
}

int loadvec(vector<int>& v, int N=-1) {
    if (N == -1) {
        N = loadint();
        if (N==0) return 0;
    }
    int bufsize = INTSPACE*N + 3;
    if (fgets(_buf, bufsize, stdin)==NULL) return 0;
    v.resize(N);

    int i=0;
    bool last = false;
    for (char *p=&_buf[0]; ;) {
        char *q = p;
        while (*q > ' ') ++q;
        if (*q == 0x0D || *q == 0x0A) last = true;
        *q = 0;
        v[i++] = atoi(p);
        if (last || i == N) break;
        p = q+1;
    }
    // assert(i <= N);
    return i;
}

#define EMPTY 0
#define D 1
#define DR 2
#define DRE 3
#define DREA 4
#define DREAM 5
//#define DREAME 6
#define DREAMER 7
#define E 8
#define ER 9
#define ERA 10
#define ERAS 11
#define ERASE 12
#define ERASER 13
#define R 14

bool solve(string& s){
    int N = s.size();
    int st = EMPTY;
    vi q;
    for (int i=0; i<N; ++i) {
        switch (s[i]){
            case 'a':
                switch (st){
                    case ER: // er -> era
                        st = ERA; break;
                    case DRE: // dre -> drea
                        st = DREA; break;
                    default:
                        return false;
                }
                break;
            case 'd':
                switch (st){
                    case EMPTY: // 0 -> d
                        st = D; break;
                    case ER: // [dream]er | d...
                        if (q.back() == DREAM) {
                            q[q.size()-1] = DREAMER; st = D; break;
                        }
                        else return false;
                    default:
                        return false;
                }
                break;
            case 'e':
                switch (st){
                    case EMPTY: // 0 -> e
                        st = E; break;
                    case DR: // dr -> dre
                        st = DRE; break;
                    case ERAS: // eras -> erase
                        q.pb(ERASE); st=EMPTY; break;

                    case ER: // [dream]er | e...
                        if (q.back() == DREAM) {
                            q[q.size()-1] = DREAMER; st = E; break;
                        }
                        else return false;
                    default:
                        return false;
                }
                break;
            case 'm':
                switch (st){
                    case DREA: // drea -> dream
                        q.pb(DREAM); st=EMPTY; break;
                    default:
                        return false;
                }
                break;
            case 'r':
                switch (st){
                    case EMPTY: // [erase] -> [eraser]
                        // rで始まる語はないのですぐに解決
                        if (q.back() == ERASE) {
                            q[q.size()-1] = ERASER; st = EMPTY; break;
                        }
                        else return false;
                    case D: // d -> dr
                        st = DR; break;
                    case E: // e -> er
                        st = ER; break;
                    default:
                        return false;
                }
                break;
            case 's':
                switch (st){
                    case ERA: // era -> eras
                        st = ERAS; break;
                    default:
                        return false;
                }
                break;

            default:
                return false;
        }
    }

    if (st == EMPTY) return true;
    if (q.empty()) return false;
    // if (q.back() == ERASE && st == R) return true;
    if (q.back() == DREAM && st == ER) return true;
    return false;
}

int main() {
    string s; cin >> s;
    cout << (solve(s) ? "YES":"NO") << endl;
    return 0;
}


Measured memory_bytes: 640