#include <iostream>
#include <algorithm>
#include <vector>
#include <tuple>

using namespace std;
using ll= long long;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t,n;
    cin>>t>>n;
    vector<pair<int,int>> me;
    vector<pair<int,int>> hu;
    for (int i = 0; i < n;i++)
    {
        int x,y;
        cin>>x>>y;
        me.push_back(make_pair(x,y));
    }
    int m;
    cin>>m;
    for (int i = 0; i < m;i++)
    {
        int x,y;
        cin>>x>>y;
        hu.push_back(make_pair(x,y));
    }
    int ans=0;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            if(me[i].first+t==hu[j].first)
            {
                if(hu[j].second<me[i].second)
                {
                    ans+=hu[j].second-hu[j].first+1;
                }
                else{
                    ans+=me[i].second-hu[j].first+1;
                }
            }
            if(me[i].first<=hu[j].first && me[i].first+t>hu[j].first)
            {
                if(me[i].second<hu[j].second)
                {
                    ans+=me[i].second-hu[j].first+1;
                }
                else{
                    ans+=hu[j].second-hu[j].first+1;
                }
            }
            if(hu[j].first<=me[i].first && hu[j].second>me[i].first)
            {
                if(me[i].second<hu[j].second)
                {
                    ans+=me[i].second-me[i].first+1;
                }
                else{
                    ans+=hu[j].second-me[i].first+1;
                }
            }
            if(me[i].second==hu[j].first && me[i].second<=me[i].first+t)
            {
                ans++;
            }
            if(me[i].first==hu[j].second)
            {
                ans++;
            }
        }
        
    }
    cout<<ans;
}
/*
1
2
1 3
7 8
2
3 7
9 10
*/