#include <cstdio>
#include <algorithm>
#include <queue>

using namespace std;

struct JOB
{
    long long dead;
    long long prof;
    bool operator <(const JOB &o) const
    {
        return dead < o.dead;
    }
};

long long N;
JOB job[100001];

int main(void)
{
    FILE *inFile = fopen("job.in", "rt");
    fscanf(inFile, "%lld", &N);
    for(long long i = 0 ; i < N ; i++)
        fscanf(inFile, "%lld%lld", &job[i].dead, &job[i].prof);
    fclose(inFile);
    job[N].dead = 0;
    job[N].prof = 0;
    N++;

    sort(job, job + N);

    priority_queue<long long> pq;
    long long curTime = 2000000000LL;
    long long profit = 0;
    for(long long i = N - 1 ; i >= 0 ; i--)
    {
        while(curTime > job[i].dead && pq.size())
        {
            curTime--;
            profit += pq.top();
            pq.pop();
        }

        curTime = job[i].dead;
        pq.push(job[i].prof);
    }

    FILE *outFile = fopen("job.out", "wt");
    fprintf(outFile, "%lld\n", profit);
    fclose(outFile);

    return 0;
}