#include <bits/stdc++.h>
using namespace std;

#define int long long

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N,K;
	cin>>N>>K;
	vector<int>v(N+3);
	for(int i=1;i<=N;i++){
		cin>>v[i];
	}
	vector<vector<int>>g(K+2);
	int M;
	cin>>M;
	for(int i=0;i<M;i++){
		int a,b;
		cin>>a>>b;
		g[a].push_back(b);
	}
	for(int i=1;i<=K;i++){
		g[0].push_back(i);
		g[i].push_back(0);
		sort(g[i].begin(),g[i].end());
	}
	vector<int>dp(N+3,-N-2);
	dp[N+1]=-1;
	dp[N+2]=-1;
	for(int i=N;i>=0;i--){
		if(binary_search(g[v[i]].begin(),g[v[i]].end(),v[i+1])){
			dp[i]=max(dp[i],dp[i+1]+1);
		}
		if(binary_search(g[v[i]].begin(),g[v[i]].end(),v[i+2])){
			dp[i]=max(dp[i],dp[i+2]+1);
		}
	}
	cout<<max(dp[0],0ll)<<'\n';
	return 0;
}