const Main = input => {
    const inp = input.split(/\n/);
    const k = parseInt(inp[0], 10);
    const s = inp[1];

    if(s.length <= k) {
        console.log(s);
    } else {
        const result = s.slice(0, k);
        console.log(`${result}...`);
    }
}
 
Main(require("fs").readFileSync("/dev/stdin", "utf8"));