题解 | Sum of Factorials

def mul(a):
    s = 1
    if a == 0 or a == 1:
        return 1
    for i in range(1,a+1):
        s *= i
    return s

def fac_s(sum, target, i):
    if sum == target:
        #print('YES')
        return True
    if sum > target:
        
        return False
    
    for j in range(i, 11):
        sum+=mul(j)
      
        if fac_s(sum, target, j+1):
            return True
        sum -= mul(j)
    return False
def p(a):
    return fac_s(0, a, 0)
while True:
    try:
        a = int(input())
        if p(a):
            print('YES')
        else:
            print('NO')
    except:
        break