fn main() {
    let amount: u32 = read();

    //1でいっぱい作る
    let num_of_1: u32 = amount / 2;
    let remaind: u32 = amount % 2;

    let mut ans = 0;
    for i in 0..(num_of_1 - 1) {
        ans += 10u32.pow(i);
    }

    if remaind == 0 {
        ans += 10u32.pow(num_of_1 - 1);
    }
    else {
        ans += 7 * 10u32.pow(num_of_1 - 1);
    }

    println!("{}", ans);
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}