#include<cstdio>
#include<set>
#include<algorithm>
#define Nmax 100001
using namespace std;
int N,ind[Nmax],t[Nmax],p[Nmax];
struct cmp2{
	bool operator()(const int&a,const int&b) const{
		return a>b;
	}
};
multiset <int,cmp2> heap;
bool cmp(const int&a,const int&b){
    return t[a]>t[b];
}
long long sol;
int main(){
	
	freopen("procesor.in","r",stdin);
	freopen("procesor.out","w",stdout);
	
	scanf("%d",&N);
	
	for(int i=1;i<=N;++i)
		scanf("%d%d",&t[i],&p[i]),
		ind[i]=i;
	
	sort(ind+1,ind+N+1,cmp);
	
	int q=1;
	for(int i=t[ind[1]];i>=1;--i){
		 while(i==t[ind[q]] && q<=N){
			 heap.insert(p[ind[q]]);
			 q++;
		 }
		 if(!heap.empty())
		 heap.erase(heap.begin());
	}
	while(!heap.empty())
		sol+=*heap.begin(),
		heap.erase(heap.begin());
	
	printf("%lld",sol);
return 0;
}