#include<bits/stdc++.h>

using namespace std;

#pragma comment(linker, "/STACK:102400000,102400000")

#define ls i<<1

#define rs ls | 1

#define mid ((ll+rr)>>1)

#define pii pair<int,int>

#define MP make_pair

typedef long long LL;

const long long INF = 1e18+1LL;

const double Pi = acos(-1.0);

const int N = 7e5+, M = 1e3+, mod = 1e9+, inf = 2e9;

int n;

LL ins[N];

struct ss{

    LL id,value;

}a[N];

bool cmp(ss s1,ss s2) {

    return s1.value>s2.value;

}

int main() {

    scanf("%d",&n);

    for(int i = ; i <= n; ++i) {

        scanf("%lld%lld",&a[i].id,&a[i].value);

    }

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

    LL ans = ;

    for(int i = ; i <= n; ++i) {

        for(int j = ; j >= ; --j) {

            if(a[i].id&(1LL<<j)) {

                if(!ins[j]) {

                    ins[j] = a[i].id;

                    break;

                }

                a[i].id ^= ins[j];

            }

        }

        if(a[i].id) ans += a[i].value;

    }

    cout<<ans<<endl;

    return ;

}