#include <bits/stdc++.h>
using namespace std;
#define int long long
bool f(bool p, bool q){
    return !(p && q);
}
signed main(){
  vector<string> S(6);
  int N = 6;
  for(int i=0;i<N;i++) cin>>S[i];
  for(int k=0;k<64;k++){
      bool ok = true;
      for(int i=0;i<N;i++)for(int j=i+1;j<N;j++)if(S[i] == S[j] && (((1<<i)&k) != ((1<<j)&k))){
          ok = false;
      }
      if(!ok) continue;
      vector<bool> A(N);
      for(int i=0;i<6;i++) A[i] = ((1<<i)&k);
      if(f(f(f(A[0],A[1]),A[2]),f(f(A[3],A[4]),A[5]))){
          cout<<"YES"<<endl;
          return 0;
      }
  }
  cout<<"NO"<<endl;
}