#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cmath>

#include<cstring>

#include<string>

#include<cstdlib>

#include<stack>

#include<vector>

#include<queue>

#include<deque>

#include<map>

#include<set>

using namespace std;

#define lck_max(a,b) ((a)>(b)?(a):(b))

#define lck_min(a,b) ((a)<(b)?(a):(b))

typedef long long LL;

const int maxn=1e6+;

LL n,ans,maxx,fa[maxn];

struct hh

{

    LL w,las;

}t[maxn];

inline LL read()

{

    LL kr=,xs=;

    char ls;

    ls=getchar();

    while(!isdigit(ls))

    {

        if(!(ls^))

            kr=-;

        ls=getchar();

    }

    while(isdigit(ls))

    {

        xs=(xs<<)+(xs<<)+(ls^);

        ls=getchar();

    }

    return xs*kr;

}

inline void out(LL xs)

{

    if(!xs) {putchar(); return;}

    if(xs<) putchar('-'),xs=-xs;

    int kr[],ls=;

    while(xs) kr[++ls]=xs%,xs/=;

    while(ls) putchar(kr[ls]+),ls--;

}

inline bool cmp(const hh&a,const hh&b)

{

    return a.w>b.w;

}

inline LL find(LL u)

{

    return u==fa[u]?u:fa[u]=find(fa[u]);

}

int main()

{

    n=read();

    for(LL i=;i<=n;i++)

        t[i].las=read(),t[i].w=read(),maxx=lck_max(maxx,t[i].las);

    for(LL i=;i<=maxx;i++) fa[i]=i;

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

    for(LL i=;i<=n;i++)

    {

        LL lck=find(t[i].las);

        if(lck)

            ans+=t[i].w,fa[lck]=lck-;

    }

    out(ans),putchar('\n');

return ;

}