C++ :

#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>

using namespace std;

inline int read()
{
    int x=0;char ch=getchar();
    while(ch<'0' || '9'<ch)ch=getchar();
    while('0'<=ch && ch<='9')x=x*10+(ch^48),ch=getchar();
    return x;
}

typedef long long ll;
const int M=1e5+9;
const int N=50009;
const ll md=1e9+7;

int n,q;
int st[N],ed[N],id[N],a[N];
ll ans,sum[N],v[N],bit1[M],bit2[M];

inline void cal(ll &x){x%=md;if(x<0)x=(x%md+md)%md;}

inline bool cmp(int x,int y)
{
    return a[x]<a[y];
}

inline void add(ll *bit,int p,ll v)
{
    for(int i=p;i<M;i+=(i&-i))
        bit[i]=((bit[i]+v)%md+md)%md;
}

inline ll query(ll *bit,int p)
{
    ll ret=0;
    for(int i=p;i;i-=(i&-i))
        (ret+=bit[i])%=md;
    return ret;
}

int main()
{
    n=read();q=read();
    int blk=sqrt(n);
    for(int i=1;i<=n;i++)
    {
        a[i]=read();
        v[i]=read()%md;
        id[i]=i;
        if(!st[i/blk])
        {
            st[i/blk]=i;
            if(i-1)
                ed[(i-1)/blk]=i-1;
        }
    }
    ed[n/blk]=n;

    for(int i=0,e=n/blk;i<=e;i++)
    {
        sort(id+st[i],id+ed[i]+1,cmp);
        sum[st[i]]=v[id[st[i]]];
        for(int j=st[i]+1;j<=ed[i];j++)
            sum[j]=(sum[j-1]+v[id[j]])%md;
    }

    ans=0;
    for(int i=n;i>=1;i--)
    {
        ans=(ans+query(bit1,a[i])+query(bit2,a[i])*v[i]%md)%md;
        add(bit1,a[i],v[i]);add(bit2,a[i],1);
    }

    while(q--)
    {
        int x=read(),y=read();
        if(x>y)swap(x,y);
        int lb=x/blk,rb=y/blk;

        if(lb==rb)
        {
            for(int i=x;i<=y;i++)
            {
                if(x<i)
                {
                    if(a[x]<a[i])
                        cal(ans+=(v[x]+v[i])%md);
                    else
                        cal(ans-=(v[x]+v[i])%md);
                }
                if(i!=x && i<y)
                {
                    if(a[i]<a[y])
                        cal(ans+=(v[y]+v[i])%md);
                    else
                        cal(ans-=(v[i]+v[y])%md);
                }
            }

            swap(a[x],a[y]);
            swap(v[x],v[y]);
            sort(id+st[lb],id+ed[lb]+1,cmp);
            sum[st[lb]]=v[id[st[lb]]];
            for(int j=st[lb]+1;j<=ed[lb];j++)
                sum[j]=(sum[j-1]+v[id[j]])%md;

            cal(ans);
            printf("%lld\n",ans);
            continue;
        }

        for(int i=x+1;i<=ed[lb];i++)
            if(a[x]<a[i])
                cal(ans+=v[x]+v[i]);
            else
                cal(ans-=v[x]+v[i]);
        for(int i=st[rb];i<=y;i++)
            if(a[x]<a[i])
                cal(ans+=v[x]+v[i]);
            else
                cal(ans-=v[x]+v[i]);

        for(int i=x+1;i<=ed[lb];i++)
            if(a[i]<a[y])
                cal(ans+=v[y]+v[i]);
            else
                cal(ans-=v[y]+v[i]);
        for(int i=st[rb];i<y;i++)
            if(a[i]<a[y])
                cal(ans+=v[y]+v[i]);
            else
                cal(ans-=v[y]+v[i]);

        for(int i=lb+1;i<rb;i++)
        {
            int l=st[i],r=ed[i],val=st[i]-1,mid;
            while(l<=r)
            {
                mid=l+r>>1;
                if(a[id[mid]]<a[x])
                    l=mid+1,val=mid;
                else
                    r=mid-1;
            }

            cal(ans+=sum[ed[i]]-2*sum[val<st[i]?0:val]%md);
            cal(ans+=v[x]*(ed[i]-2*val+st[i]-1)%md);

            l=st[i],r=ed[i],val=st[i]-1;
            while(l<=r)
            {
                mid=l+r>>1;
                if(a[id[mid]]<a[y])
                    l=mid+1,val=mid;
                else
                    r=mid-1;
            }
            cal(ans+=2*sum[val<st[i]?0:val]%md-sum[ed[i]]);
            cal(ans+=v[y]*(2*val-ed[i]-st[i]+1)%md);
        }

        swap(a[x],a[y]);
        swap(v[x],v[y]);
        sort(id+st[lb],id+ed[lb]+1,cmp);
        sort(id+st[rb],id+ed[rb]+1,cmp);

        sum[st[lb]]=v[id[st[lb]]];
        for(int j=st[lb]+1;j<=ed[lb];j++)
            sum[j]=(sum[j-1]+v[id[j]])%md;
        sum[st[rb]]=v[id[st[rb]]];
        for(int j=st[rb]+1;j<=ed[rb];j++)
            sum[j]=(sum[j-1]+v[id[j]])%md;
        cal(ans);
        printf("%lld\n",ans);
    }

    return 0;
}