fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let a = (0..n).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp = temp.trim();
            temp.chars().collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();
    let mut b = String::new();
    std::io::stdin().read_line(&mut b).ok();
    let m: usize = b.trim().parse().unwrap();
    let b = (0..m).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp = temp.trim();
            temp.chars().collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();

    let length = a.iter().map(|v| v.len()).sum::<usize>();
    let mut result = 0usize;
    let mut res = vec![];
    for i in 0..n {
        let mut left = vec![];
        let mut right = vec![];
        a[i].iter().for_each(|&c| left.push(c));
        while left.len() < length || right.len() < length {
            if left.len() < right.len() {
                let idx = left.len();
                if let Some(x) = a.iter().filter(|&v| v[0] == right[idx]).nth(0) {
                    x.iter().for_each(|&c| left.push(c));
                } else {
                    break;
                }
            } else if left.len() > right.len() {
                let idx = right.len();
                if let Some(x) = b.iter().filter(|&v| v[0] == left[idx]).nth(0) {
                    x.iter().for_each(|&c| right.push(c));
                } else {
                    break;
                }
            } else {
                println!("-1");
                return;
            }
        }
        if left.len() == length && right.len() == length {
            result += 1;
            res = left.clone().to_owned();
        }
    }
    if result == 1 {
        println!("{}", res.iter().map(|c| c.to_string()).collect::<Vec<_>>().join(""));
    } else {
        println!("-1");
    }
}