import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop, std.bitmanip;

immutable long MOD = 998244353;

void main() {
    auto N = readln.chomp.to!int;
    auto S = readln.chomp;

    if (N == 1) {
        writeln("Yes");
        return;
    }

    auto cnt = new int[](26);
    foreach (s; S) cnt[s - 'a'] += 1;

    bool ok = false;
    foreach (i; 0..26) if (cnt[i] >= 2) ok = true;

    writeln(ok ? "Yes" : "No");
}
