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

#define TYPE_OF( VAR ) remove_const<remove_reference<decltype( VAR )>::type >::type
#define UNTIE ios_base::sync_with_stdio( false ); cin.tie( nullptr ) 
#define CEXPR( LL , BOUND , VALUE ) constexpr const LL BOUND = VALUE 
#define CIN( LL , A ) LL A; cin >> A 
#define ASSERT( A , MIN , MAX ) assert( ( MIN ) <= A && A <= ( MAX ) ) 
#define CIN_ASSERT( A , MIN , MAX ) CIN( TYPE_OF( MAX ) , A ); ASSERT( A , MIN , MAX ) 
#define FOR( VAR , INITIAL , FINAL_PLUS_ONE ) for( TYPE_OF( FINAL_PLUS_ONE ) VAR = INITIAL ; VAR < FINAL_PLUS_ONE ; VAR ++ ) 
#define REPEAT( HOW_MANY_TIMES ) FOR( VARIABLE_FOR_REPEAT , 0 , HOW_MANY_TIMES ) 
#define QUIT return 0 
#define COUT( ANSWER ) cout << ( ANSWER ) << "\n"; 
#define RETURN( ANSWER ) COUT( ANSWER ); QUIT 

template <int L>
void IncrementPath( int ( &path )[L] )
{
  constexpr const int L_m = L - 1;
  FOR( k , 0 , L_m ){
    int& path_k = path[k];
    if( ++path_k < path[k+1] ){
      return;
    }
    path_k = 0;
  }
  path[L_m]++;
  return;
}

#define CHECK_LOOP( NUM , CHECK_VALID )		\
  REPEAT( path_ ## NUM ## _bound ){		\
    count = 0;					\
    FOR( n , 0 , N ){				\
      vertex[n] = 0;				\
    }						\
    FOR( k , 0 , NUM ){				\
      int path_k = path[k];			\
      int& vij0 = vertex[ij0[path_k]];		\
      if( vij0 == 1 ){				\
	count++;				\
      }						\
      vij0++;					\
      int& vij1 = vertex[ij1[path_k]];		\
      if( vij1 == 1 ){				\
	count++;				\
      }						\
      vij1++;					\
    }						\
    if( count == NUM ){				\
      CHECK_VALID;				\
    }						\
    IncrementPath( path );			\
  }						\
						\


#define CHECK_VALID_FOUR RETURN( "Yes" ) 
#define CHECK_VALID_THREE FOR( i , 0 , N ){ if( vertex[i] != vertex_exception[i] ){ RETURN( "Yes" ); } }

#define CHECK_LOOP_FOUR CHECK_LOOP( four , CHECK_VALID_FOUR )
#define CHECK_LOOP_THREE CHECK_LOOP( three , CHECK_VALID_THREE )

int main()
{
  UNTIE;
  CEXPR( int , bound_N , 4 );
  CIN_ASSERT( N , 1 , bound_N );
  if( N < 3 ){
    RETURN( "No" );
  }
  CEXPR( int , bound_M , ( bound_N * ( bound_N - 1 ) ) / 2 );
  CIN_ASSERT( M , 0 , bound_M );
  if( M < 3 ){
    RETURN( "No" );
  }
  int ij0[bound_M];
  int ij1[bound_M];
  FOR( m , 0 , M ){
    CIN( int , ij0m );
    CIN( int , ij1m );
    assert( 0 <= ij0m && ij0m < ij1m && ij1m < N );
    FOR( k , 0 , m ){
      assert( ij0[k] != ij0m || ij1[k] != ij1m );
    }
    ij0[m] = ij0m;
    ij1[m] = ij1m;
  }
  int count;
  int vertex[bound_N];
  if( N == 4 ){
    CEXPR( int , four , 4 );
    int path[four] = { 0 , 1 , 2 , 3 };
    int path_four_bound = ( ( ( ( ( M * ( M - 1 ) ) / 2 ) * ( M - 2 ) ) / 3 ) * ( M - 3 ) ) / 4;
    CHECK_LOOP_FOUR;
  }
  int vertex_exception[bound_N] = {};
  CEXPR( int , three , 3 );
  REPEAT( three ){
    CIN_ASSERT( i_v , 0 , N - 1 );
    vertex_exception[i_v] += 2;
  }
  int path[three] = { 0 , 1 , 2 };
  int path_three_bound = ( ( ( M * ( M - 1 ) ) / 2 ) * ( M - 2 ) ) / 3;
  CHECK_LOOP_THREE;
  RETURN( "No" );
}