#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using namespace placeholders; using LL = long long; using ULL = unsigned long long; using VI = vector< int >; using VVI = vector< vector< int > >; using VS = vector< string >; using SS = stringstream; using PII = pair< int, int >; using VPII = vector< pair< int, int > >; template < typename T = int > using VT = vector< T >; template < typename T = int > using VVT = vector< vector< T > >; template < typename T = int > using LIM = numeric_limits< T >; template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; } template < typename T > inline ostream& operator<<( ostream &s, const vector< T > &v ){ for ( int i = 0; i < int( v.size() ); ++i ){ s << ( " " + !i ) << v[i]; } return s; } template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; }; template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); }; #define REP2( i, n ) REP3( i, 0, n ) #define REP3( i, m, n ) for ( int i = ( int )( m ); i < ( int )( n ); ++i ) #define GET_REP( a, b, c, F, ... ) F #define REP( ... ) GET_REP( __VA_ARGS__, REP3, REP2 )( __VA_ARGS__ ) #define FOR( e, c ) for ( auto &e : c ) #define ALL( c ) ( c ).begin(), ( c ).end() #define AALL( a, t ) ( t* )a, ( t* )a + sizeof( a ) / sizeof( t ) #define DRANGE( c, p ) ( c ).begin(), ( c ).begin() + p, ( c ).end() #define SZ( v ) ( (int)( v ).size() ) #define PB push_back #define EM emplace #define EB emplace_back #define BI back_inserter #define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() ) #define MP make_pair #define fst first #define snd second #define DUMP( x ) cerr << #x << " = " << ( x ) << endl LL sqdist( const PII &p, const PII &q ) { const LL dy = p.fst - q.fst, dx = p.snd - q.snd; return dy * dy + dx * dx; } int main() { cin.tie( 0 ); ios::sync_with_stdio( false ); VVT< VPII > buckets( 1024, VT< VPII >( 1024 ) ); int N; // cin >> N; scanf( "%d", &N ); REP( i, N ) { int x, y; // cin >> x >> y; scanf( "%d %d", &x, &y ); const int by = y / 100 + 1, bx = x / 100 + 1; const PII p( y, x ); bool ok = true; REP( dy, -1, 2 ) { REP( dx, -1, 2 ) { FOR( q, buckets[ by + dy ][ bx + dx ] ) { ok &= 20 * 20 <= sqdist( p, q ); } } } if ( ok ) { buckets[ by ][ bx ].PB( p ); } } int res = 0; FOR( row, buckets ) { FOR( ps, row ) { res += SZ( ps ); } } // cout << res << endl; printf( "%d\n", res ); return 0; }