#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> Pii;
typedef pair<int, ll> Pil;
typedef pair<ll, ll> Pll;
typedef pair<ll, int> Pli;
typedef vector<vector<ll>> Mat;
#define fi first
#define se second
const ll MOD = 1e9 + 7;
const ll MOD2 = 998244353;
const ll MOD3 = 1812447359;
const ll INF = 1ll << 62;
const double PI = 2 * asin(1);
void yes() { printf("yes\n"); }
void no() { printf("no\n"); }
void Yes() { printf("Yes\n"); }
void No() { printf("No\n"); }
void YES() { printf("YES\n"); }
void NO() { printf("NO\n"); }

char s[5][5];
int di[4] = {-1, 0, 1, 0}, dj[4] = {0, -1, 0, 1};

int main() {
  for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 3; j++) {
      cin >> s[i][j];
    }
  }

  for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 3; j++) {
      for (int k = 0; k < 4; k++) {
        if (s[i][j] == s[i + di[k]][j + dj[k]]) {
          No();
          return 0;
        }
      }
    }
  }
  Yes();

  return 0;
}