#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char e[100001];

main(){
	char*mmap();
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	while(*rp++!=10);
	long d=3;
	while(*rp){
		long i=0,a=0;
		for(long c;c=*rp++,c!='\n';){
			long b=(c&1)+1;
			a|=b;
			e[i++]|=b;
		}
		d&=a;
	}
	if(d!=3){
		for(long i=0;e[i];++i){
			if(e[i]!=3){
				write(1,"NO",2);
				_exit(0);
			}
		}
	}
	write(1,"YES",3);
	_exit(0);
}