#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define ld long double
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pdd pair<ld, ld>
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second

const int NMAX = 1005;
const int inf = 1 << 30;

int a[NMAX], dp[NMAX];

vector<int> v[NMAX];

int main() {
    cin.sync_with_stdio(false);

    int d, n, m;
    cin >> d >> n >> m;

    for (int i = 1; i <= n; i++)
        cin >> a[i];

    sort(a + 1, a + n + 1);

    for (; m; m--) {
        int x, y;
        cin >> x >> y;

        int mini = -1;
        int maxi = -1;

        for (int i = 1; i <= n; i++)
            if (a[i] >= x && a[i] <= y) {
                mini = i;
                break;
            }
        for (int i = n; i; i--)
            if (a[i] >= x && a[i] <= y) {
                maxi = i;
                break;
            }

        if (mini != -1)
            v[maxi].pb(mini);
    }

    for (int i = 1; i <= d; i++)
        dp[i] = inf;

    for (int i = 1; i <= n; i++)
        for (auto it : v[i])
            if (dp[it - 1] != inf)
                dp[i] = min(dp[i], dp[it - 1] + 1);

    cout << dp[n];

    return 0;
}