function Main(input)
{
    const temp = input.trim().split("\n");
    const k = parseInt(temp[0], 10);
    const s = String(temp[1]);

    if (s.length > k) {
        let ans = s.slice(0, k);
        console.log(ans + "...");
    } else {
        console.log(s)
    }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));