void main() {
    int n = readln.chomp.to!int;
    string[] w = new string[n];
    int ok = true;
    foreach (i; 0 .. n) {
        string s = readln.chomp;
        if (i > 0) {
            if (s[0] != w[i-1][$-1] || w.canFind(s)) {
                ok = false;
                break;
            }
        }
        w[i] = s;
    }
    writeln(ok ? "Yes" : "No");
}

import std.stdio;
import std.string;
import std.array;
import std.conv;
import std.algorithm;
import std.range;
import std.math;
import std.container;
import std.typecons;