#include<iostream>

#include<cstdio>

#include<cstdlib>

#include<cmath>

#include<cstring>

#include<algorithm>

using namespace std;

#define N 500010

#define M N<<2

#define ll long long

#define P 1000000007

ll read()

{

    ll x=,f=;char c=getchar();

    while (c<''||c>'') {if (c=='-') f=-;c=getchar();}

    while (c>=''&&c<='') x=(x<<)+(x<<)+(c^),c=getchar();

    return x*f;

}

int n,p[M],dfn[M],low[M],stk[M],Set[M],L[M],R[M],root,t,cnt,top,tot,ans=;

bool flag[M];

ll a[N],b[N];

struct data{int to,nxt;

}edge[M<<];

struct data2{int l,r;

}tree[M];

void addedge(int x,int y){t++;edge[t].to=y,edge[t].nxt=p[x],p[x]=t;}

void build(int &k,int l,int r)

{

    if (l==r) {k=l;return;}

    k=++cnt;

    int mid=l+r>>;

    build(tree[k].l,l,mid);

    build(tree[k].r,mid+,r);

    addedge(k,tree[k].l),addedge(k,tree[k].r);

}

void add(int k,int l,int r,int x,int y,int p)

{

    if (l==x&&r==y) {addedge(p,k);return;}

    int mid=l+r>>;

    if (y<=mid) add(tree[k].l,l,mid,x,y,p);

    else if (x>mid) add(tree[k].r,mid+,r,x,y,p);

    else add(tree[k].l,l,mid,x,mid,p),add(tree[k].r,mid+,r,mid+,y,p);

}

void tarjan(int k)

{

    dfn[k]=low[k]=++cnt;stk[++top]=k;flag[k]=;

    for (int i=p[k];i;i=edge[i].nxt)

    if (!dfn[edge[i].to]) tarjan(edge[i].to),low[k]=min(low[k],low[edge[i].to]);

    else if (flag[edge[i].to]) low[k]=min(low[k],dfn[edge[i].to]);

    if (dfn[k]==low[k])

    {

        tot++;L[tot]=n+,R[tot]=;

        while (stk[top]!=k)

        {

            Set[stk[top]]=tot;

            if (stk[top]<=n) L[tot]=min(L[tot],stk[top]),R[tot]=max(R[tot],stk[top]);

            flag[stk[top]]=;

            top--;

        }

        Set[k]=tot;if (k<=n) L[tot]=min(L[tot],k),R[tot]=max(R[tot],k);flag[k]=,top--;

    }

}

namespace newgraph

{

    int p[M]={},degree[M]={},q[M],t=;

    struct data{int to,nxt;}edge[M<<];

    void addedge(int x,int y){t++;edge[t].to=y,edge[t].nxt=p[x],p[x]=t;degree[y]++;}

    void topsort()

    {

        int head=,tail=;

        for (int i=;i<=tot;i++) if (!degree[i]) q[++tail]=i;

        while (tail<tot)

        {

            int x=q[++head];

            for (int i=p[x];i;i=edge[i].nxt)

            {

                degree[edge[i].to]--;

                if (!degree[edge[i].to]) q[++tail]=edge[i].to;

            }

        }

    }

    void dp()

    {

        for (int i=tot;i>=;i--)

        {

            int x=q[i];

            for (int j=p[x];j;j=edge[j].nxt)

            L[x]=min(L[x],L[edge[j].to]),R[x]=max(R[x],R[edge[j].to]);

        }

    }

}

int main()

{

#ifndef ONLINE_JUDGE

    freopen("bzoj5017.in","r",stdin);

    freopen("bzoj5017.out","w",stdout);

    const char LL[]="%I64d\n";

#else

    const char LL[]="%lld\n";

#endif

    n=read();

    for (int i=;i<=n;i++) a[i]=read(),b[i]=read();

    cnt=n;

    build(root,,n);

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

    {

        int x,y;

        int l=,r=i;

        while (l<=r)

        {

            int mid=l+r>>;

            if (a[i]-b[i]<=a[mid]) x=mid,r=mid-;

            else l=mid+;

        }

        l=i,r=n;

        while (l<=r)

        {

            int mid=l+r>>;

            if (a[i]+b[i]>=a[mid]) y=mid,l=mid+;

            else r=mid-;

        }

        add(root,,n,x,y,i);

    }

    t=cnt;cnt=;

    for (int i=;i<=t;i++) if (!dfn[i]) tarjan(i);

    for (int k=;k<=t;k++)

        for (int i=p[k];i;i=edge[i].nxt)

        if (Set[k]!=Set[edge[i].to]) newgraph::addedge(Set[k],Set[edge[i].to]);

    newgraph::topsort();

    newgraph::dp();

    for (int i=;i<=n;i++) ans=(ans+1ll*i*(R[Set[i]]-L[Set[i]]+))%P;

    cout<<ans;

    return ;

}