inp = require('fs').readFileSync('/dev/stdin', 'utf8').split('\n')
N = inp.shift() * 1
w = {}
w[inp[0]] = 1
last = inp[0][inp[0].length-1]
f = 1
for (i=1; i<N; i++) {
    word = inp[i]
    w[word] = (w[word] || 0) + 1
    if (w[word] == 2 || last != word[0]) {
        f = 0
        break;
    }
    last = word[word.length - 1]
}
console.log(f ? 'Yes' : 'No')