struct interval { int st,dr; } v[10002],u[10002];

int comp(interval a, interval b)
{
    return a.st<b.st;
}

#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream f("bunicul.in");
ofstream g("bunicul.out");
int m,n,r,s,k,d,p,i,x;

int main()
{
    f>>m>>n>>r;
    for(i=1;i<=n;i++)
    {
         f>>v[i].st>>v[i].dr;
         s+=v[i].dr-v[i].st+1;
    }
    s=m-s+1;
    g<<s<<'\n';
    sort(v+1,v+n+1,comp);
    v[0].dr=-1;
    v[n+1].st=m+1;
    i=1;
    for(k=1;k<=r;k++)
    {
        f>>x;
        d=v[i].st-v[i-1].dr-1;
        while(d<x&&i<=n) {
            i++;
            d=v[i].st-v[i-1].dr-1;
        }
        if(x<=d)
        {
            u[++p].st=v[i-1].dr+1;
            u[p].dr=u[p].st+x-1;
            v[i-1].dr+=x;
        }
        else break;
    }
    if(p<r) g<<p<<" "<<u[p].dr;
    else for(i=1;i<=r;i++)
        g<<u[i].st<<" "<<u[i].dr<<" ";
    g.close();

    return 0;
}