A, B, C = map(int, input().split())

# AN - B = C
# AN = C ( <= B)

ans = []

if B >= C and C % A == 0:
    ans.append(C // A)

if (B + C) % A == 0:
    ans.append((B + C) // A)


if len(ans) == 0:
    print(-1)
else:
    for a in ans:
        print(a)