# include <bits/stdc++.h>
# define NR 1005
using namespace std;
//ifstream f("sick.in");
//ofstream g("sick.out");
vector <int> v[NR];
int i,j,n,m,x,y,minn,D;
int minim[NR], sick[NR];
int main ()
{
    cin>>D>>n>>m;
    for (i=1; i<=n; ++i)
        cin>>sick[i];
    sort (sick+1, sick+n+1);

    for (i=1; i<=m; ++i) {
        cin>>x>>y;

        for (j=1; j<=n; ++j) //x
            if (sick[j] >= x) {x=sick[j]; break;}

        for (j=n; j>=1; --j) //y
            if (sick[j] <= y) {y=sick[j]; break;}

        if (x > y) continue;

        v[y].push_back(x);
    }
    for (i=1; i<=n; ++i) {
        minn=654564;
        for (auto &x: v[sick[i]])
            minn=min(minn, minim[x]);

        minim[x]=minn+1;
    }
    cout<<minim[sick[n]]<<"\n";

    return 0;
}