#include <stdio.h>
#include <unordered_set>

int main() {
  FILE *fin = fopen( "hashuri.in", "r" );
  FILE *fout = fopen( "hashuri.out", "w" );

  int q;
  std::unordered_set<int> mata;
  for( scanf( "%d", &q ); q--; ){
    int task, x;
    fscanf( fin, "%d%d", &task, &x );
    if( task == 1 )
      mata.insert( x );
    else if( task == 2 )
      mata.erase( x );
    else
      fprintf( fout, "%d\n", int(mata.count( x )) );
  }

  fclose( fin );
  fclose( fout );
  return 0;
}