#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

int c[];

struct point

{

    int x;

    int v;

} p[];

bool cmp(point p1,point p2)

{

    if(p1.x !=p2.x)

        return p1.x>p2.x;

    else

        return p1.v<p2.v;

}

int lowbit(int x)

{

    return x & (-x);

}

void update(int i,int val)

{

    while(i<=)

    {

        c[i]+=val;

        i+=lowbit(i);

    }

}

int Sum(int i)

{

    int s=;

    while(i>)

    {

        s += c[i];

        i -= lowbit(i);

    }

    return s;

}

int main()

{

    //freopen("input.txt","r",stdin);

    int i,n;

    while(scanf("%d",&n)!=EOF)

    {

        memset(c,,sizeof(c));

        long long int ans = ;

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

            scanf("%d%d",&p[i].x,&p[i].v);

        sort(p,p+n,cmp);

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

        {

            ans += Sum(p[i].v);

            update(p[i].v+,);

        }

        printf("%lld\n",ans);

    }

    return ;

}