#include<cstdio>
#include<cstring>
int n;
char s[110][20];
int main() {
	scanf("%d",&n);
	for(register int i=0;i<n;++i)scanf("%s",s[i]);
	for(register int i=1;i<n;++i)if(s[i][0]!=s[i-1][strlen(s[i-1])-1]) return puts("No"),0;
	for(register int i=0;i<n;++i)for(register int j=0;j<i;++j)if(!strcmp(s[i],s[j])) return puts("No"),0;
	return puts("Yes"),0;
}