#include <algorithm>
#include <iostream>
#include <iomanip>
#include <limits.h>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
#include <stack>

using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep1(i, n) for (int i = 1; i < n + 1; i++)
#define all(A) A.begin(), A.end()
#define itr(A, l, r) A.begin() + l, A.begin() + r
#define debug(var) cout << #var << " = " << var << endl;
typedef long long ll;

int main(void)
{
    vector<vector<char>> maze(5, vector<char>(5, '*'));
    rep(i, 3)
    {
        string s;
        cin >> s;
        rep(j, 3)
        {
            maze[i + 1][j + 1] = s[j];
        }
    }
    auto print_maze = [](auto maze)
    {
        int n = maze.size();
        int m = maze[0].size();
        rep(i, n)
        {
            rep(j, m) { cout << maze[i][j]; }
            cout << endl;
        }
    };
    // print_maze(maze);
    vector<int> di = {1, -1, 0, 0};
    vector<int> dj = {0, 0, 1, -1};
    rep(i, 3)
    {
        rep(j, 3)
        {
            rep(k, 4)
            {
                int ni = i + 1 + di[k];
                int nj = j + 1 + dj[k];
                if (maze[i+1][j+1] == maze[ni][nj])
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
        }
    }
    cout << "Yes" << endl;
}