var toInt = x=>parseInt(x,10);
var toIntArr = arr=>arr.map(x=>toInt(x));
var abs = x=>x>0?x:-x;
function min(){var rest = arguments,val=rest[0];for(var i=1;i<rest.length;i++)if(rest[i]<val)val = rest[i];return val}
function max(){var rest = arguments,val=rest[0];for(var i=1;i<rest.length;i++)if(rest[i]>val)val = rest[i];return val}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
 
function Main(input){
	var input = input.split('\n');
	var n = toInt(input[0]);
	var ws = [];
	for(var i = 0; i < n; i++){
		ws[i] = input[i+1];
	}
	var x,y;
	for(var i = 1; i < n; i++){
		for(var j = 0; j < i; j++){
			if(ws[i]===ws[j]){
				console.log('No');
				return 0;
			}
		}
		x = ws[i-1];
		y = ws[i];
		if(x[x.length-1]!==y[0]){
			console.log('No');
			return 0;
		}
	}
	
	console.log('Yes');
}