#include<bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 typedef unsigned int uint;

 typedef unsigned long long ull;

 typedef long double ld;

 typedef pair<int,int> PII;

 typedef pair<ll,ll> Pll;

 typedef vector<int> VI;

 typedef vector<PII> VII;

 typedef pair<ll,ll>P;

 #define N  100010

 #define M  1000000

 #define INF 1e9

 #define fi first

 #define se second

 #define MP make_pair

 #define pb push_back

 #define pi acos(-1)

 #define mem(a,b) memset(a,b,sizeof(a))

 #define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++)

 #define per(i,a,b) for(int i=(int)a;i>=(int)b;i--)

 #define lowbit(x) x&(-x)

 #define Rand (rand()*(1<<16)+rand())

 #define id(x) ((x)<=B?(x):m-n/(x)+1)

 #define ls p<<1

 #define rs p<<1|1

 #define fors(i) for(auto i:e[x]) if(i!=p)

 const int MOD=1e9+,inv2=(MOD+)/;

       double eps=1e-;

       int dx[]={-,,,};

       int dy[]={,,-,};

 int read()

 {

    int v=,f=;

    char c=getchar();

    while(c<||<c) {if(c=='-') f=-; c=getchar();}

    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();

    return v*f;

 }

 ll readll()

 {

    ll v=,f=;

    char c=getchar();

    while(c<||<c) {if(c=='-') f=-; c=getchar();}

    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();

    return v*f;

 }

 struct node

 {

     ll x;

     int y;

 }a[N];

 bool cmp(node a,node b)

 {

     return a.y>b.y;

 }

 struct base

 {

     ll d[],p[];

     int cnt;

     base()

     {

         mem(d,);

         mem(p,);

         cnt=;

     }

     bool insert(ll x)

     {

         //if(x==0) return 0;

         per(i,,)

          if(x>>i&)

          {

              if(!d[i])

              {

                  d[i]=x;

                  break;

              }

              x^=d[i];

          }

         return x>;

     }

 }T;

 int main()

 {

     int n=read();

     rep(i,,n) scanf("%lld%d",&a[i].x,&a[i].y);

     sort(a+,a+n+,cmp);

     base T;

     int ans=;

     rep(i,,n) if(T.insert(a[i].x)) ans+=a[i].y;

     printf("%d\n",ans);

     return ;

 }