#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;

#define maxn 100100
#define inf (1000000000)

int d, n, m;
int f[maxn];
int dp[maxn];
vector<int> v[maxn];

int main()
{
    scanf("%d%d%d", &d, &n, &m);

    for(int i=1; i<=n; ++i)
    {
        int x;
        scanf("%d", &x);
        ++f[x];
    }

    for(int i=1; i<=d; ++i)
    {
        dp[i]=inf;
        f[i]+=f[i-1];
    }

    for(int i=1; i<=m; ++i)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        v[x].push_back(y);
    }

    int sol=0, mxfar=-1, pt=1, mxc = -1;

    for(int i=1; i<=d; ++i)
    {
        if(f[i]==f[i-1])
            dp[i]=min(dp[i], dp[i-1]);

        for(int j=0; j<v[i].size(); ++j)
            if(f[v[i][j]]!=f[i-1])
                dp[v[i][j]]=min(dp[v[i][j]], dp[i-1]+1);
    }

    printf("%d\n", dp[d]);

    return 0;
}