function Main(input) {
    input = input.trim().split("\n");
    input.shift();
    const s = input[0].trim();
    let d = {};
    for (let i = 0; i < s.length; ++i) {
        let key = s[i];
        if (!d[key])
            d[key] = {ch: key, count:1};
        else
            d[key].count++;
    }
    for (let x of Object.values(d)) {
        if (x.count >= 2) {
            console.log("Yes");
            return false;
        }
    }
    console.log("No");
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));