#40475: 參考答案 Python
'''
https://zerojudge.tw/ShowProblem?problemid=e555
e555. 10170 - The Hotel with Infinite Rooms
'''
while True:
try:
S, D = map(int, input().split())
while True:
if D>0:
D -= S
S += 1
if D<=0:
print(S - 1)
break
except:
break
#40476: Re: 參考答案 Python
乾這樣會TLE 抱歉沒測過就丟上來