def isqrt(n):
    if n<=0: return 0
    if n<4: return 1
    x,y=0,n
    while x!=y and x+1!=y:
        x,y=y,(n//y+y)//2
    return x
n=8*int(raw_input())+1
q=isqrt(n)
print('NO' if q*q!=n else 'YES\n'%(q//2))