public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int N = sc . nextInt ( ) ;
  long K = sc . nextLong ( ) ;
  Map < Integer , Long > map = new TreeMap < > ( ) ;
  for ( int i = 0 ;
  i < N ;
  i ++ ) {
    int a = sc . nextInt ( ) ;
    long b = sc . nextInt ( ) ;
    if ( map . containsKey ( a ) ) {
      b += map . get ( a ) ;
    }
    map . put ( a , b ) ;
  }
  for ( Map . Entry entry : map . entrySet ( ) ) {
    K -= ( long ) entry . getValue ( ) ;
    if ( K <= 0 ) {
      out . print ( entry . getKey ( ) ) ;
      return ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int N = sc . nextInt ( ) ; long K = sc . nextLong ( ) ; Map < Integer , Long > map = new TreeMap < > ( ) ; for ( int i = 0 ; i < N ; i ++ ) { int a = sc . nextInt ( ) ; long b = sc . nextInt ( ) ; if ( map . containsKey ( a ) ) { b += map . get ( a ) ; } map . put ( a , b ) ; } for ( Map . Entry entry : map . entrySet ( ) ) { K -= ( long ) entry . getValue ( ) ; if ( K <= 0 ) { out . print ( entry . getKey ( ) ) ; return ; } } }
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