#include <iostream>
#include <string>
#include <stdio.h>
#include <stdint.h>
using namespace std;

using ll = long long;

#define CIN( LL , A ) LL A; cin >> A 
#define FOR_LL( VAR , INITIAL , FINAL_PLUS_ONE ) for( ll VAR = INITIAL ; VAR < FINAL_PLUS_ONE ; VAR ++ ) 
#define RETURN( ANSWER ) cout << ( ANSWER ) << endl; return 0 

int main()
{
  string A[6];
  FOR_LL( i , 0 , 6 ){
    cin >> A[i];
  }
  ll num[6] = {};
  ll num_lim = 1;
  FOR_LL( i , 1 , 6 ){
    string& Ai = A[i];
    bool searching = true;
    FOR_LL( j , 0 , i ){
      if( Ai == A[j] ){
	num[i] = num[j];
	j = i;
	searching = false;
      }
    }
    if( searching ){
      num[i] = num_lim;
      num_lim++;
    }
  }
  ll N = 1;
  FOR_LL( i , 0 , num_lim ){
    N *= 2;
  }
  bool b[6];
  FOR_LL( v , 0 , N ){
    FOR_LL( i , 0 , num_lim ){
      b[i] = ( v >> i ) % 2 == 1;
    }
    if( ! ( ( ! ( ( ! ( b[num[0]] && b[num[1]] ) ) && b[num[2]] ) ) && ( ! ( ( ! ( b[num[3]] && b[num[4]] ) ) && b[num[5]] ) ) ) ){
      RETURN( "YES" );
    }
  }
  RETURN( "NO" );
}