Buggy python submission (verdict: Time Limit Exceeded):
s=list(str(input()))
b=0
while len(s)>=5:
  if s[-1]=='r' and len(s)>=7:
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif len(s)==6:
    if ''.join(s)=='eraser':
      print('YES')
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0:
  print('YES')
elif b!=1:
  print('NO')

Fixed submission:
s=list(str(input()))
b=0
while len(s)>=7:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0 or (len(s)==6 and ''.join(s)=='eraser') or (len(s)==5 and ''.join(s)=='dream') or (len(s)==5 and ''.join(s)=='erase'):
  print('YES') 
elif b!=1:
  print('NO')

Buggy python submission (verdict: Time Limit Exceeded):
s=list(str(input()))
b=0
while len(s)>=5:
  if s[-1]=='r' and len(s)>=7:
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif len(s)==6:
    if ''.join(s)=='eraser':
      print('YES')
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0:
  print('YES')
elif b!=1:
  print('NO')

Fixed submission:
s=list(str(input()))
b=0
while len(s)>=7:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0 or (len(s)==6 and ''.join(s)=='eraser') or (len(s)==5 and ''.join(s)=='dream') or (len(s)==5 and ''.join(s)=='erase'):
  print('YES') 
elif b!=1:
  print('NO')

Buggy python submission (verdict: Time Limit Exceeded):
s=list(str(input()))
b=0
while len(s)>=5:
  if s[-1]=='r' and len(s)==6:
    if ''.join(s)=='eraser':
      print('YES')
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0:
  print('YES')
elif b!=1:
  print('NO')

Fixed submission:
s=list(str(input()))
b=0
while len(s)>=7:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0 or (len(s)==6 and ''.join(s)=='eraser') or (len(s)==5 and ''.join(s)=='dream') or (len(s)==5 and ''.join(s)=='erase'):
  print('YES') 
elif b!=1:
  print('NO')

Buggy python submission (verdict: Time Limit Exceeded):
s=list(str(input()))
b=0
while len(s)>=5:
  if s[-1]=='r' and len(s)>=7:
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='r':
    if ''.join(s)=='eraser':
      print('YES')
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0:
  print('YES')
elif b!=1:
  print('NO')

Fixed submission:
s=list(str(input()))
b=0
while len(s)>=7:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0 or (len(s)==6 and ''.join(s)=='eraser') or (len(s)==5 and ''.join(s)=='dream') or (len(s)==5 and ''.join(s)=='erase'):
  print('YES') 
elif b!=1:
  print('NO')

Buggy python submission (verdict: Runtime Error):
s=list(str(input()))
b=0
while len(s)>=5:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0:
  print('YES')
elif b!=1:
  print('NO')

Fixed submission:
s=list(str(input()))
b=0
while len(s)>=7:
  if s[-1]=='r':
    sd=[s[-7],s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    se=[s[-6],s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dreamer':
      del s[-7:]
    elif ''.join(se)=='eraser':
      del s[-6:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='m':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='dream':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break
  elif s[-1]=='e':
    sd=[s[-5],s[-4],s[-3],s[-2],s[-1]]
    if ''.join(sd)=='erase':
      del s[-5:]
    else:
      print('NO')
      b+=1
      break  
  else:
    print('NO')
    b+=1
    break
if len(s)==0 or (len(s)==6 and ''.join(s)=='eraser') or (len(s)==5 and ''.join(s)=='dream') or (len(s)==5 and ''.join(s)=='erase'):
  print('YES') 
elif b!=1:
  print('NO')