拟阵证明，线性基性质，线性基中任意子集异或和不为0，所以从大到小加入就好
/**************************************************************
Problem: 2460
User: zhhx
Language: C++
Result: Accepted
Time:24 ms
Memory:832 kb
****************************************************************/
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<cstdlib>
using namespace std;
typedef long long ll;
int n;
struct aa
{
ll num;int val;
}a[1005];
bool cmp(aa a,aa b) {return a.val>b.val;}
ll b[65];
int main()
{
scanf("%d",&n);
for (int i=1;i<=n;i++) scanf("%lld%d",&a[i].num,&a[i].val);
sort(a+1,a+n+1,cmp);
int ans=0;
for (int i=1;i<=n;i++)
{ ll p=a[i].num;
for (int j=63;j>=0;j--) if (p&(1ll<<j))
{ if (b[j]) p^=b[j];
else {b[j]=p;ans+=a[i].val;break;}
}
}
printf("%d",ans);
return 0;
}