n = int(input())
now = 1
did = False
for i in range(1, 1000):
    if (did):
        break
    l = 1
    r = 10000000000000000000000000
    for _ in range(1, 200):
        m = (l + r) // 2
        k = (m + i) * (m + i) - m * m
        if (k <= n):
            l = m
        else:
            r = m

    if ((l + i) * (l + i) - l * l == n):
        print(1)
        did = True

if (did == False):
    print(-1)