A, B, C = map(int, input().split())
if A < 0:
    A *= -1
    B *= -1
    C *= -1
t = -B // (2 * A)
if A * t**2 + B * t + C >= 0:
    left = t
else:
    ok = -(10**18)
    assert A * ok**2 + B * ok + C >= 0
    ng = t
    assert A * ng**2 + B * ng + C < 0
    assert ok < ng
    while ok + 1 < ng:
        mid = (ok + ng) // 2
        if A * mid**2 + B * mid + C >= 0:
            ok = mid
        else:
            ng = mid
    left = ok
t = (-B + 2 * A - 1) // (2 * A)
if A * t**2 + B * t + C >= 0:
    right = t
else:
    ok = 10**18
    assert A * ok**2 + B * ok + C >= 0
    ng = t
    assert A * ng**2 + B * ng + C < 0
    assert ng < ok
    while ng + 1 < ok:
        mid = (ok + ng) // 2
        if A * mid**2 + B * mid + C >= 0:
            ok = mid
        else:
            ng = mid
    right = ok
print(right - left - 1)