#include<bits/stdc++.h>

using namespace std;

const int MAXN = ;

inline int rd(){

    int x=,f=;char ch=getchar();

    while(!isdigit(ch)) {f=ch=='-'?:;ch=getchar();}

    while(isdigit(ch))  {x=(x<<)+(x<<)+ch-'';ch=getchar();}

    return f?x:-x;

}

int n,res;

long long ans;

struct Data{

    int p,t;

}data[MAXN];

priority_queue<int,vector<int>,greater<int> > Q;

inline bool cmp(Data A,Data B){

    return A.t==B.t?A.p>B.p:A.t<B.t;

}

int main(){

    n=rd();

    for(int i=;i<=n;i++) data[i].t=rd(),data[i].p=rd();

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

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

        if(res<data[i].t) ans+=data[i].p,res++,Q.push(data[i].p);

        else {

            int x=Q.top();

            if(data[i].p>x) ans+=data[i].p-x,Q.pop(),Q.push(data[i].p);

        }

    }

    cout<<ans;

    return ;

}