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

T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;

bool calc(string[] ss) {
    bool[string] d = [ss[0]: true];
    for (int i = 1; i < ss.length; i++) {
        if (ss[i] in d) return false;
        if (ss[i-1][$-1] != ss[i][0]) return false;

        d[ss[i]] = true;
    }
    return true;
}

void main() {
    int n = readint;
    string[] ss;
    for (int i = 0; i < n; i++) {
        ss ~= read!string;
    }

    writeln(calc(ss) ? "Yes" : "No");
}
