#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using P = pair<int, int>;
using ll = long long;

int main(){
	vector<string> s(3);
	rep(i, 3) cin >> s[i];
	
	char t = s[0][0];
	rep(i, 3){
		rep(j, 3){
			if(i == 0 && j == 0) continue;
			
			if(t == s[i][j]){
				cout << "No" << endl;
				return 0;
			} else {
				t = s[i][j];
			}
		}
	}
	cout << "Yes" << endl;
}