pub fn read<T: std::str::FromStr>() -> T {
    use std::io::Read;
    std::io::stdin()
        .lock()
        .by_ref()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>()
        .parse::<T>()
        .ok()
        .unwrap()
}
pub fn extgcd(a: i64, b: i64) -> (i64, i64, i64) {
    if b == 0 {
        return if a < 0 { (-a, -1, 0) } else { (a, 1, 0) };
    }
    let (g, s, t) = extgcd(b, a % b);
    (g, t, s - a / b * t)
}
pub fn crt(mr: &[(i64, i64)]) -> Option<(i64, i64)> {
    use std::mem::swap;
    let (mut m, mut r) = (1, 0);
    for &(mut m1, mut r1) in mr.iter() {
        assert!(m1 > 0);
        r1 %= m1;
        if m < m1 {
            // needed to avoid overflow
            swap(&mut r, &mut r1);
            swap(&mut m, &mut m1);
        }
        if m % m1 == 0 {
            if r % m1 == r1 {
                continue;
            }
            return None;
        }
        let (g, inv_u, _) = extgcd(m, m1);
        if (r1 - r) % g != 0 {
            return None;
        }
        let u1 = m1 / g;
        let x = (r1 - r) / g * inv_u % u1;
        r += x * m;
        m *= u1;
    }
    if r < 0 {
        r += m;
    }
    debug_assert!(0 <= r && r < m);
    Some((m, r))
}
pub fn main() {
    use std::io::Write;
    let out = std::io::stdout();
    let writer = &mut std::io::BufWriter::new(out.lock());
    let mr: Vec<_> = (0..3)
        .map(|_| {
            let r: i64 = read();
            let m: i64 = read();
            (m, r)
        })
        .collect();
    if let Some((m, mut r)) = crt(&mr) {
        if r == 0 {
            r += m;
        }
        writeln!(writer, "{}", r).unwrap();
    } else {
        writeln!(writer, "{}", -1).unwrap();
    }
}