fn main() {
    input! {
        n: usize,
        p: [(i64, i64); n],
    }
    let mut solver = Garner::new();
    for (r, m) in p {
        solver.push(m, r);
    }
    const MOD: i64 = 1_000_000_007;
    let mut ans = solver.find(MOD).unwrap_or(-1);
    if solver.digit.iter().all(|p| *p == 0) {
        ans = solver.base.iter().fold(0, |s, a| s * *a % MOD);
    }
    println!("{}", ans);
}

// X = sum_{0<=i} digit[i] * prod_{j<i} base[j]
//
pub struct Garner {
    base: Vec<i64>,
    digit: Vec<i64>,
}

impl Garner {
    pub fn new() -> Self {
        Self {
            base: vec![],
            digit: vec![],
        }
    }
    // X = r (mod m)
    // という条件の追加
    pub fn push(&mut self, m: i64, r: i64) {
        assert!(0 <= r && r < m && m < (1i64 << 31));
        if self.base.last().map_or(false, |p| *p <= 0) {
            self.base.push(-1);
            self.digit.push(-1);
            return;
        }
        let mut a = 0;
        let mut b = 1;
        for (base, digit) in self.base.iter().zip(self.digit.iter()) {
            a = (a + *digit * b) % m;
            b = b * *base % m;
        }
        let r = (r - a).rem_euclid(m);
        let (p, _, g) = calc(b, m);
        if r % g != 0 {
            self.base.push(-1);
            self.digit.push(-1);
        } else {
            let m = m / g;
            self.base.push(m);
            self.digit.push((p * (r / g)).rem_euclid(m));
        }
    }
    pub fn pop(&mut self) {
        self.base.pop();
        self.digit.pop();
    }
    // X mod m
    pub fn find(&self, m: i64) -> Option<i64> {
        assert!(0 < m && m < (1i64 << 31));
        if self.base.last().map_or(false, |p| *p <= 0) {
            return None;
        }
        let mut s = 0;
        for (base, digit) in self.base.iter().zip(self.digit.iter()).rev() {
            s = (s * *base + *digit) % m;
        }
        Some(s)
    }
}

// return (a, b, g)
// g = gcd(x, y)
// ax + by = gcd(x, y)
fn calc(x: i64, y: i64) -> (i64, i64, i64) {
    if y == 0 {
        return (x.signum(), 0, x.abs());
    }
    let q = x.div_euclid(y);
    let r = x.rem_euclid(y);
    let p = calc(y, r);
    (p.1, p.0 - q * p.1, p.2)
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------