Buggy python submission (verdict: Time Limit Exceeded):
s = input()

checkedList = []
noCheckedList = []
tmp_index = 0

while(True) :

	if( s[tmp_index] == 'd' ) :
		if ( not (tmp_index in checkedList) ) and ( s[tmp_index:tmp_index+5] == 'dream' ) and ( s[tmp_index:tmp_index+7] == 'dreamer' ) :
			noCheckedList.append(tmp_index)
			checkedList.append(tmp_index)
			tmp_index += 7
		elif s[tmp_index:tmp_index+5] == 'dream' :
			tmp_index += 5
		elif s[tmp_index:tmp_index+7] == 'dreamer' :
			tmp_index += 7
	elif( s[tmp_index] == 'e' ) :
		if ( not (tmp_index in checkedList) )  and ( s[tmp_index:tmp_index+5] == 'erase' ) and ( s[tmp_index:tmp_index+6] == 'eraser' ) :
			noCheckedList.append(tmp_index)
			checkedList.append(tmp_index)
			tmp_index += 6
		elif s[tmp_index:tmp_index+5] == 'erase' :
			tmp_index += 5
		elif s[tmp_index:tmp_index+6] == 'eraser' :
			tmp_index += 6
	else :
		if len(noCheckedList) != 0 :
			tmp_index = noCheckedList.pop() + 5
			continue
		else :
			print('NO')
			break
	if tmp_index == len(s):
		print('YES')
		break
	elif len(s) - tmp_index < 5 :
		if len(noCheckedList) != 0 :
			tmp_index = noCheckedList.pop() + 5
		else :
			print('NO')
			break

Fixed submission:
s = input()

tmp_index = 0

while(len(s) - tmp_index > 4) :

	if( s[tmp_index] == 'd' ) :
		if s[tmp_index:tmp_index+7] == 'dreamer' :
			if ( s[tmp_index + 5:tmp_index + 10] == 'erase' ):
				tmp_index += 5
			else :
				tmp_index += 7
		elif s[tmp_index:tmp_index+5] == 'dream' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
			
	elif( s[tmp_index] == 'e' ) :
		if  s[tmp_index:tmp_index + 6] == 'eraser' :
			tmp_index += 6
		elif s[tmp_index:tmp_index+5] == 'erase' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
	else :
		tmp_index = len(s) - 1
	if len(s) == tmp_index :
		print('YES')
	elif len(s) - tmp_index < 5 :
		print('NO')

Buggy python submission (verdict: Runtime Error):
def checks(s) :
	ret = 'NO'
	if len(s) < 5 :
		return 'NO'
	elif( s[0] == 'd' ) :
		#dream
		if s[:5] == 'dream' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#dreamer
		if ( len(s) > 6 ) and ( ret != 'YES' ) and s[:7] == 'dreamer' :
			if len(s) != 7 :
				ret = checks(s[7:])
			else :
				return 'YES'
	elif( s[0] == 'e' ) :
		#erase
		if s[:5] == 'erase' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#eraser
		if ( len(s) > 5 ) and ( ret != 'YES' ) and s[:6] == 'eraser' :
			if len(s) != 6 :
				ret = checks(s[6:])
			else :
				return 'YES'
	else :
		return ret

S = input()

print(checks(S))

Fixed submission:
s = input()

tmp_index = 0

while(len(s) - tmp_index > 4) :

	if( s[tmp_index] == 'd' ) :
		if s[tmp_index:tmp_index+7] == 'dreamer' :
			if ( s[tmp_index + 5:tmp_index + 10] == 'erase' ):
				tmp_index += 5
			else :
				tmp_index += 7
		elif s[tmp_index:tmp_index+5] == 'dream' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
			
	elif( s[tmp_index] == 'e' ) :
		if  s[tmp_index:tmp_index + 6] == 'eraser' :
			tmp_index += 6
		elif s[tmp_index:tmp_index+5] == 'erase' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
	else :
		tmp_index = len(s) - 1
	if len(s) == tmp_index :
		print('YES')
	elif len(s) - tmp_index < 5 :
		print('NO')

Buggy python submission (verdict: Runtime Error):
def checks(s) :
	ret = 'NO'
	if len(s) < 5 :
		return 'NO'
	elif( s[0] == 'd' ) :
		#dream
		if s[:5] == 'dream' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#dreamer
		if ( len(s) > 6 ) and ( ret != 'YES' ) and (s[:7] == 'dreamer') :
			if len(s) != 7 :
				ret = checks(s[7:])
			else :
				return 'YES'
	elif( s[0] == 'e' ) :
		#erase
		if s[:5] == 'erase' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#eraser
		if ( len(s) > 5 ) and ( ret != 'YES' ) and ( s[:6] == 'eraser' ) :
			if len(s) != 6 :
				ret = checks(s[6:])
			else :
				return 'YES'
	return ret

S = input()

print(checks(S))

Fixed submission:
s = input()

tmp_index = 0

while(len(s) - tmp_index > 4) :

	if( s[tmp_index] == 'd' ) :
		if s[tmp_index:tmp_index+7] == 'dreamer' :
			if ( s[tmp_index + 5:tmp_index + 10] == 'erase' ):
				tmp_index += 5
			else :
				tmp_index += 7
		elif s[tmp_index:tmp_index+5] == 'dream' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
			
	elif( s[tmp_index] == 'e' ) :
		if  s[tmp_index:tmp_index + 6] == 'eraser' :
			tmp_index += 6
		elif s[tmp_index:tmp_index+5] == 'erase' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
	else :
		tmp_index = len(s) - 1
	if len(s) == tmp_index :
		print('YES')
	elif len(s) - tmp_index < 5 :
		print('NO')

Buggy python submission (verdict: Runtime Error):
def checks(s) :
	ret = 'NO'
	if len(s) < 5 :
		return 'NO'
	elif( s[0] == 'd' ) :
		#dream
		if s[:5] == 'dream' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#dreamer
		if ( len(s) > 6 ) and ( ret != 'YES' ) and s[:7] == 'dreamer' :
			if len(s) != 7 :
				ret = checks(s[7:])
			else :
				return 'YES'
	elif( s[0] == 'e' ) :
		#erase
		if s[:5] == 'erase' :
			if len(s) != 5 :
				ret = checks(s[5:])
			else :
				return 'YES'
		#eraser
		if ( len(s) > 5 ) and ( ret != 'YES' ) and s[:6] == 'eraser' :
			if len(s) != 6 :
				ret = checks(s[6:])
			else :
				return 'YES'
	return ret

S = input()

print(checks(S))

Fixed submission:
s = input()

tmp_index = 0

while(len(s) - tmp_index > 4) :

	if( s[tmp_index] == 'd' ) :
		if s[tmp_index:tmp_index+7] == 'dreamer' :
			if ( s[tmp_index + 5:tmp_index + 10] == 'erase' ):
				tmp_index += 5
			else :
				tmp_index += 7
		elif s[tmp_index:tmp_index+5] == 'dream' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
			
	elif( s[tmp_index] == 'e' ) :
		if  s[tmp_index:tmp_index + 6] == 'eraser' :
			tmp_index += 6
		elif s[tmp_index:tmp_index+5] == 'erase' :
			tmp_index += 5
		else :
			tmp_index = len(s) - 1
	else :
		tmp_index = len(s) - 1
	if len(s) == tmp_index :
		print('YES')
	elif len(s) - tmp_index < 5 :
		print('NO')