function Main(input) {
    const x = parseInt(input.replace("\n", ""));
    const ab = [2, 2, -1, -1, 2, -1, -1];
    let p = 0;
    let d = 0;
    let ans = 0;
    for (let i = 0; i < 100; i++) {
        d = ab[i % 7]
        p += d;
        ans += Math.abs(d);
        if (p == x) break;
    }
    console.log(ans);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));