# find if n*(n-1)/2 can be separated into two adjacent numbers
def adjacent(num):
    a=round(num**(1/2.0),0)
    if a*(a+1)==num:
        return True

god_num = 0
for n in range(2,N+1):
    if adjacent(n*(n-1)/2):
        god_num+=1
        print n
print(god_num)g