#include <fstream>
#include <algorithm>

using namespace std;

pair <int,pair <int,int> > leave[1005];
int n,d,m,viz[1005],nr;
void read();
void solve();
void write();
int cmp(pair <int,pair <int,int> >,pair <int,pair <int,int> >);
int main(){
    read();
    solve();
    write();
    return 0;
}

void read(){
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    #endif // ONLINE_JUDGE
    scanf("%d%d%d",&d,&n,&m);
    for (int i=1;i<=n;i++){
        int day;
        scanf("%d",&day);
        viz[day]=1;
    }
    for (int i=1;i<=m;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        leave[i]=make_pair(0,make_pair(x,y));
    }
}

void solve(){
    for (int i=1;i<=m;i++){
        for (int j=leave[i].second.first;j<=leave[i].second.second;j++){
            leave[i].first+=viz[j];
        }
    }
    sort(leave+1,leave+m+1,cmp);
    int rest=0;
    while (rest<n){
        rest+=leave[1].first;
        leave[1].first=0;
        nr++;
        for (int j=leave[1].second.first;j<=leave[1].second.second;j++){
            viz[j]=0;
        }
        for (int i=1;i<=m;i++){
            leave[i].first=0;
            for (int j=leave[i].second.first;j<=leave[i].second.second;j++){
                leave[i].first+=viz[j];
            }
        }
        sort(leave+1,leave+m+1,cmp);
        m--;
    }
}

int cmp(pair <int, pair <int,int> > p1,pair <int, pair <int,int> > p2){
    return p1.first>p2.first;
}

void write(){
    printf("%d",nr);
}