#![allow(non_snake_case)]
#![allow(dead_code)]
#![allow(unused_macros)]
#![allow(unused_imports)]

use std::str::FromStr;
use std::io::*;
use std::collections::*;
use std::cmp::*;

struct Scanner<I: Iterator<Item = char>> {
    iter: std::iter::Peekable<I>,
}

macro_rules! exit {
    () => {{
        exit!(0)
    }};
    ($code:expr) => {{
        if cfg!(local) {
            writeln!(std::io::stderr(), "===== Terminated =====")
                .expect("failed printing to stderr");
        }
        std::process::exit($code);
    }}
}

impl<I: Iterator<Item = char>> Scanner<I> {
    pub fn new(iter: I) -> Scanner<I> {
        Scanner {
            iter: iter.peekable(),
        }
    }

    pub fn safe_get_token(&mut self) -> Option<String> {
        let token = self.iter
            .by_ref()
            .skip_while(|c| c.is_whitespace())
            .take_while(|c| !c.is_whitespace())
            .collect::<String>();
        if token.is_empty() {
            None
        } else {
            Some(token)
        }
    }

    pub fn token(&mut self) -> String {
        self.safe_get_token().unwrap_or_else(|| exit!())
    }

    pub fn get<T: FromStr>(&mut self) -> T {
        self.token().parse::<T>().unwrap_or_else(|_| exit!())
    }

    pub fn vec<T: FromStr>(&mut self, len: usize) -> Vec<T> {
        (0..len).map(|_| self.get()).collect()
    }

    pub fn mat<T: FromStr>(&mut self, row: usize, col: usize) -> Vec<Vec<T>> {
        (0..row).map(|_| self.vec(col)).collect()
    }

    pub fn char(&mut self) -> char {
        self.iter.next().unwrap_or_else(|| exit!())
    }

    pub fn chars(&mut self) -> Vec<char> {
        self.get::<String>().chars().collect()
    }

    pub fn mat_chars(&mut self, row: usize) -> Vec<Vec<char>> {
        (0..row).map(|_| self.chars()).collect()
    }

    pub fn line(&mut self) -> String {
        if self.peek().is_some() {
            self.iter
                .by_ref()
                .take_while(|&c| !(c == '\n' || c == '\r'))
                .collect::<String>()
        } else {
            exit!();
        }
    }

    pub fn peek(&mut self) -> Option<&char> {
        self.iter.peek()
    }
}

fn ext_gcd(a: i64, b: i64) -> (i64, i64, i64) {
    if b == 0 {
        return (a, 1, 0);
    }
    let (q, r) = (a.div_euclid(b), a.rem_euclid(b));
    let (d, s, t) = ext_gcd(b, r);
    let x = t;
    let y = s - q*t;
    (d, x, y)
}

fn crt(b: Vec<i64>, m: Vec<i64>) -> Option<(i64, i64)> {
    let (mut r, mut lcm) = (0, 1);
    let len = b.len();
    for i in 0..len {
        let (d, p, _q) = ext_gcd(lcm, m[i]);
        if (b[i] - r) % d != 0 {
            return None;
        }
        let s = (b[i] - r) / d;
        r = r + (s * p % (m[i]/d))*lcm;
        lcm = lcm * (m[i]/d);
    }
    Some((r.rem_euclid(lcm), lcm))
}

fn main() {
    let cin = stdin();
    let cin = cin.lock();
    let mut sc = Scanner::new(cin.bytes().map(|c| c.unwrap() as char));
    let mut X: Vec<i64> = Vec::with_capacity(3);
    let mut Y: Vec<i64> = Vec::with_capacity(3);
    for _ in 0..3 {
        X.push(sc.get());
        Y.push(sc.get());
    }
    if let Some(ans) = crt(X, Y) {
        if ans.0 == 0 {
            println!("{}", ans.1);
        } else {
            println!("{}", ans.0);
        }
    } else {
        println!("-1");
    }
}