from math import isqrt
n, m = map(int, input().split())
if n == 1:
    print('NaN')
    exit()
def f(x):
    # t*sqrt(n) - 1 < x
    # t^2 < (x+1)^2 / n
    tmx = isqrt(max(0, ((x+1) ** 2 + n - 1) // n - 1))
    return x - tmx >= m

l = 0
r = 1
while not f(r):
    l = r
    r *= 2
while r - l > 1:
    c = (l + r) // 2
    if f(c):
        r = c
    else:
        l = c
print(r)