#include<stdio.h>
int main(){
  int n,i,c;
  char w,a,b;
  while(scanf("%d",&n)!=EOF){
    int d[10][2]={0};
    for(i=0;i<n;i++){
      scanf("%c%c%c",&w,&a,&b);
      if(a==b)d[a-'0'][1]=1;
      else{
	d[a-'0'][0]++;
	d[b-'0'][0]++;
      }
    }
    c=0;
    for(i=0;i<10;i++){
      if(d[i][0]%2)c++;
      if(!d[i][0]&&d[i][1])c=3;
    }
    if(c<3)printf("Yes\n");
    else   printf("No\n");
  }
  return 0;
}