use proconio::input;
use std::cmp::max;

fn main(){
    input!{
        n: u64,
        ratios: [(u64, u64); n],
    };

    let mut a = 1;
    let mut t = 1;

    for (r_t, r_a) in ratios {
        let x = max((r_t + t - 1) / r_t, (r_a + a - 1) / r_a);
        t = r_t * x;
        a = r_a * x;
    }

    println!("{}", {a + t});
}