import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
n, k = na()
K = k
ans = float("inf")
if k >= n:
    s = 1
    r = 0
    k -= n
    for i in range(n-1, 0, -1):
        if s == 1:
            if k >= i:
                k -= i
            else:
                s = 0
                r += 1
        else:
            if k <= i * (i - 1)//2:
                pass
            else:
                k -= i
                s = 1
                r += 1
    if s == 0:
        r += 1
    ans = r
k = K
if k <= n * (n - 1)//2:
    s = 0
    r = 1
    for i in range(n-1, 0, -1):
        #print(s)
        if s == 1:
            if k >= i:
                k -= i
            else:
                s = 0
                r += 1
        else:
            if k <= i * (i - 1)//2:
                pass
            else:
                k -= i
                s = 1
                r += 1
    if s == 0:
        r += 1

print(min(ans, r)//2)