import std.stdio;
import std.conv;
import std.string;

void main() {
    auto n = readln.chomp.to!int;
    string[] words = [];
    auto ans = "Yes";
    foreach (i; 0..n) {
        auto word = readln.chomp;
        foreach (w; words) {
            if (w == word){
                "No".writeln;
                return;
            }
        }
        words ~= word;
    }

    foreach (i; 1..n){
        if (words[i - 1][$ - 1] != words[i][0]) {
            ans = "No";
            break;
        }
    }
    ans.writeln;
}
