// 入力フォーマットチェック１
#include<bits/stdc++.h>
using namespace std;

using ll = long long;

#define CIN( LL , A ) LL A; cin >> A 
#define UNTIE ios_base::sync_with_stdio( false ); cin.tie( nullptr ) 
#define FOR( VAR , INITIAL , FINAL_PLUS_ONE ) for( remove_const<remove_reference<decltype( FINAL_PLUS_ONE )>::type >::type 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 RETURN( ANSWER ) cout << ( ANSWER ) << "\n"; QUIT 

#define CHECK_REDUNDANT_INPUT string VARIABLE_FOR_CHECK_REDUNDANT_INPUT = ""; cin >> VARIABLE_FOR_CHECK_REDUNDANT_INPUT; assert( VARIABLE_FOR_CHECK_REDUNDANT_INPUT == "" ); assert( ! cin );
// #define CHECK_REDUNDANT_INPUT string VARIABLE_FOR_CHECK_REDUNDANT_INPUT = ""; getline( cin , VARIABLE_FOR_CHECK_REDUNDANT_INPUT ); assert( VARIABLE_FOR_CHECK_REDUNDANT_INPUT == "" ); assert( ! cin );


int main()
{
  UNTIE;
  constexpr const int bound_M = 1000;
  CIN( int , N );
  assert( 1 <= N && N <= bound_M );
  CIN( int , M );
  assert( 1 <= M && M <= bound_M );
  constexpr const ll bound_Aj = 1000000001;
  REPEAT( N ){
    FOR( j , 0 , M ){
      CIN( ll , Aj );
      assert( 1 <= Aj && Aj < bound_Aj );
    }
  }
  CHECK_REDUNDANT_INPUT;
  RETURN( "YES" );
}