N,K=map(int,input().split())

ANS=N

A=[0]*N

x=K
for i in range(N,0,-1):
    if x>=i:
        A[i-1]=1
        x-=i


count=0
for i in range(N):
    if A[i]==0 and (i==0 or A[i-1]==1):
        count+=1

ANS=min(ANS,count)


A=[0]*N

x=K
for i in range(N,0,-1):
    if x>=i:
        A[i-1]=1
        x-=i
    else:
        break

for i in range(1,N+1):
    if x>=i and A[i-1]==0:
        A[i-1]=1
        x-=i

if x==0:
    count=0
    for i in range(N):
        if A[i]==0 and (i==0 or A[i-1]==1):
            count+=1

    ANS=min(ANS,count)

print(ANS)