Buggy python submission (verdict: Runtime Error):
s = inpput()
while True:
	S = s
	if len(S) < 5:
		print('NO')
		break
	if S == 'dream' or S == 'erase':
		print('YES')
		break
	else:
		if S[0] == 'd':
			if S[7] == 'a':
				T ='dream'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'dreamer'
				if S[:7] == T:
					S = S[7:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		if S[0] == 'e':
			if len(S) >= 6 and S[5] == 'r':
				T = 'eraser'
				if S[:6] == T:
					S = S[6:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'erase'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		else:
			print('NO')
			break

Fixed submission:
S=input()
 
S=S.replace('eraser','')
S=S.replace('erase','')
S=S.replace('dreamer','')
S=S.replace('dream','')
 
if S=='':
    print('YES')
else:
    print('NO')

Buggy python submission (verdict: Runtime Error):
s = input()
while True:
	S = s
	if len(S) < 5:
		print('NO')
		break
	if S == 'dream' or S == 'erase':
		print('YES')
		break
	else:
		if S[0] == 'd':
			if S[7] == 'a':
				T ='dream'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'dreamer'
				if S[:7] == T:
					S = S[7:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		if S[0] == 'e':
			if len(S) >= 6 and S[5] == 'r':
				T = 'eraser'
				if S[:6] == T:
					S = S[6:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'erase'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		else:
            print('NO')
            break

Fixed submission:
S=input()
 
S=S.replace('eraser','')
S=S.replace('erase','')
S=S.replace('dreamer','')
S=S.replace('dream','')
 
if S=='':
    print('YES')
else:
    print('NO')

Buggy python submission (verdict: Runtime Error):
s = input()
while True:
	S = s
	if len(S) < 5:
		print('NO')
		break
	if S == 'dream' or S == 'erase':
		print('YES')
		break
	else:
		if S[0] == 'd':
			if S[7] == 'a':
				T ='dream'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'dreamer'
				if S[:7] == T:
					S = S[7:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		if S[0] == 'e':
			if len(S) >= 6 and S[5] == 'r':
				T = 'eraser'
				if S[:6] == T:
					S = S[6:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
			else:
				T = 'erase'
				if S[:5] == T:
					S = S[5:]
					T = ""
					if S == "":
						print('YES')
						break
					s = S
				else:
					print('NO')
					break
		else:
			print('NO')
            break


Fixed submission:
S=input()
 
S=S.replace('eraser','')
S=S.replace('erase','')
S=S.replace('dreamer','')
S=S.replace('dream','')
 
if S=='':
    print('YES')
else:
    print('NO')