#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<deque>
#include<vector>
#include<string>
#include<math.h>
using namespace std;

#define INF 1000000000
#define lint long long
#define pb push_back
#define mp make_pair
#define MOD 1000000007

pair <lint,lint> a[100005];
lint prod[100005];
lint t[33000],t1[33000],tp[33000],tv[33000];

void update(int v,lint val)
{
    t[v]+=val;
    t1[v]++;
    v/=2;
    while(v)
    {
        t[v]=t[2*v]+t[2*v+1];
        t1[v]=t1[2*v]+t1[2*v+1];
        v/=2;
    }
}
void update1(int v,lint val)
{
    tp[v]+=val;
    v/=2;
    while(v)
    {
        tp[v]=tp[2*v]+tp[2*v+1];
        v/=2;
    }
}
void update2(int v,lint val)
{
    tv[v]+=val;
    v/=2;
    while(v)
    {
        tv[v]=tv[2*v]+tv[2*v+1];
        v/=2;
    }
}
lint get(int v,int li,int ri,int l,int r)
{
    if(li>r||ri<l)
        return 0;
    if(li>=l&&ri<=r)
        return t[v];
    return get(2*v,li,(li+ri)/2,l,r)+get(2*v+1,(li+ri)/2+1,ri,l,r);
}
lint gett1(int v,int li,int ri,int l,int r)
{
    if(li>r||ri<l)
        return 0;
    if(li>=l&&ri<=r)
        return t1[v];
    return gett1(2*v,li,(li+ri)/2,l,r)+gett1(2*v+1,(li+ri)/2+1,ri,l,r);
}
lint getp(int v,int li,int ri,int l,int r)
{
    if(li>r||ri<l)
        return 0;
    if(li>=l&&ri<=r)
        return tp[v];
    return getp(2*v,li,(li+ri)/2,l,r)+getp(2*v+1,(li+ri)/2+1,ri,l,r);
}
lint getv(int v,int li,int ri,int l,int r)
{
    if(li>r||ri<l)
        return 0;
    if(li>=l&&ri<=r)
        return tv[v];
    return getv(2*v,li,(li+ri)/2,l,r)+getv(2*v+1,(li+ri)/2+1,ri,l,r);
}
int main()
{
    int n,i,j,p=16384;
    scanf("%d",&n);
    for(i=1;i<=n;++i)
    {
        scanf("%lld %lld",&a[i].first,&a[i].second);
    }
    sort(a+1,a+1+n);
    for(i=1;i<=n;++i)
    {
        prod[i]=a[i].first*a[i].second;
    }
    lint ans=0;
    for(i=1;i<=n;++i)
    {
        lint sum1,sum2,cntpoqr,cntmec=0,sumprpoqr,sumprmec;

        cntpoqr=gett1(1,p,p+p-1,p,a[i].second+p-1);
        cntmec=gett1(1,p,p+p-1,a[i].second+p,p+p-1);

        sumprpoqr=get(1,p,p+p-1,p,a[i].second+p-1);
        sumprmec=get(1,p,p+p-1,a[i].second+p,p+p-1);

        sum1=a[i].first*(cntpoqr*a[i].second-sumprpoqr);
        sum1+=a[i].first*(sumprmec-cntmec*a[i].second);

        sum2=-getv(1,p,p+p-1,a[i].second+p,p+p-1)*a[i].second+getp(1,p,p+p-1,a[i].second+p,p+p-1);
        sum2+=getv(1,p,p+p-1,p,a[i].second+p-1)*a[i].second-getp(1,p,p+p-1,p,a[i].second+p-1);

        ans+=sum1-sum2;

        update(a[i].second+p-1,a[i].second);
        update1(a[i].second+p-1,prod[i]);
        update2(a[i].second+p-1,a[i].first);

    }
    cout<<ans;
    return 0;
}