There is a kangaroo at coordinate 0 on an infinite number line that runs from left to right, at time 0. During the period between time i-1 and time i, the kangaroo can either stay at his position, or perform a jump of length exactly i to the left or to the right. That is, if his coordinate at time i-1 is x, he can be at coordinate x-i, x or x+i at time i. The kangaroo's nest is at coordinate X, and he wants to travel to coordinate X as fast as possible. Find the earliest possible time to reach coordinate X.
x = int(input())
check = 0
for i in range(1, 1+x):
  check += i
  if check >= i:
    print(i)
    break
X = int(input())

ans = 0
check = 0
for i in range(1, 10**7):
    ans += i
    check += 1
    if X <= ans:
        print(check)
        break