#include <cstdio>

#include <algorithm>

#include <queue>

const int maxn = ;

int n, now;

long long ans;

struct st1 {

    long long d, p;

} a[maxn];

struct st2 {

    long long data;

    bool operator<(const st2 rhs) const {

        return data > rhs.data;

    }

};

std::priority_queue<st2> hp;

bool cmp(const st1 & aa, const st1 & ss) {

    return aa.d < ss.d;

}

int main(void) {

    //freopen("in.txt", "r", stdin);

    scanf("%d", &n);

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

        scanf("%lld%lld", &a[i].d, &a[i].p);

    }

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

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

        if (now < a[i].d) {

            ans += a[i].p;

            ++now;

            hp.push((st2){a[i].p});

        }

        else if (a[i].p > hp.top().data) {

            ans += a[i].p - hp.top().data;

            hp.pop();

            hp.push((st2){a[i].p});

        }

    }

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

    return ;

}