1 /**************************************************************
2 Problem: 2460
3 User: idy002
4 Language: C++
5 Result: Accepted
6 Time:68 ms
7 Memory:832 kb
8 ****************************************************************/
9
10 #include <cstdio>
11 #include <algorithm>
12 #define N 1010
13 using namespace std;
14
15 typedef unsigned long long dnt;
16
17 struct Pair {
18 dnt v;
19 int w;
20 void read() { scanf( "%llu%d", &v, &w ); }
21 bool operator<( const Pair &p ) const { return w<p.w; }
22 };
23
24 int n;
25 Pair prs[N];
26 dnt a[N], b[N]; int tot;
27
28 bool ok() {
29 for( int i=0; i<tot; i++ )
30 b[i] = a[i];
31 for( int i=60,j=0; i>=0 && j<tot; i-- ) {
32 for( int k=j; k<tot; k++ )
33 if( (b[k]>>i) & 1 ) {
34 swap( b[k], b[j] );
35 break;
36 }
37 if( (b[j]>>i)==1 ) {
38 for( int k=j+1; k<tot; k++ )
39 if( (b[k]>>i) & 1 ) {
40 b[k] ^= b[j];
41 if( b[k]==0 ) return false;
42 }
43 j++;
44 }
45 }
46 return true;
47 }
48 int main() {
49 scanf( "%d", &n );
50 for( int i=1; i<=n; i++ )
51 prs[i].read();
52 sort( prs+1, prs+1+n );
53 int ans = 0;
54 for( int i=n; i>=1; i-- ) {
55 a[tot++] = prs[i].v;
56 if( ok() ) {
57 ans += prs[i].w;
58 } else {
59 tot--;
60 }
61 }
62 printf( "%d\n", ans );
63 }
