#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000


int main() {
    
	vector<string> s(3);
	rep(i,3)cin>>s[i];
	rep(i,3){
		rep(j,3){
			if(i!=2){
				if(s[i][j]==s[i+1][j]){
					cout<<"No"<<endl;
					return 0;
				}
			}
			if(j!=2){
				if(s[i][j]==s[i][j+1]){
					cout<<"No"<<endl;
					return 0;
				}
			}
			
		}
	}
	cout<<"Yes"<<endl;
	
    return 0;
}