1 #include<vector>
 2 #include<cstdio>
 3 #include<iostream>
 4 #include<cmath>
 5 #include<queue>
 6 #include<stack>
 7 #include<cmath>
 8 #include<algorithm>
 9 #define numm ch-48
10 #define pd putchar(' ')
11 #define pn putchar('\n')
12 #define pb push_back
13 #define fi first
14 #define se second
15 #define fre1 freopen("1.txt","r",stdin)
16 #define fre2 freopen("2.txt","w",stdout)
17 using namespace std;
18 template <typename T>
19 void read(T &res) {
20     bool flag=false;char ch;
21     while(!isdigit(ch=getchar())) (ch=='-')&&(flag=true);
22     for(res=numm;isdigit(ch=getchar());res=(res<<1)+(res<<3)+numm);
23     flag&&(res=-res);
24 }
25 template <typename T>
26 void write(T x) {
27     if(x<0) putchar('-'),x=-x;
28     if(x>9) write(x/10);
29     putchar(x%10+'0');
30 }
31 const int maxn=1010;
32 const int N=60;
33 const int inf=0x3f3f3f3f;
34 const int INF=0x7fffffff;
35 typedef long long ll;
36 ll d[70];
37 struct node {
38     ll x;
39     int y;
40     bool operator<(const node &b) const{
41         return y>b.y;
42     }
43 }a[maxn];
44 bool add(ll x) {
45     for(int i=60;~i;i--)
46         if(x&(1LL<<i))
47             if(d[i]) x^=d[i];
48             else {
49                 d[i]=x;
50                 return true;
51             }
52     return false;
53 }
54 int main()
55 {
56     int ans=0,n;
57     read(n);
58     for(int i=1;i<=n;i++)
59         read(a[i].x),read(a[i].y);
60     sort(a+1,a+1+n);
61     for(int i=1;i<=n;i++)
62         if(add(a[i].x)) ans+=a[i].y;
63     write(ans);pn;
64     return 0;
65 }