#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
#include <fstream>
#include <bitset>
   
using namespace std;
   
 
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
#define ten(n) ((long long)(1e##n))
#define bin(n) (1ull << (n))
#define erep(i, n) for (int i = 0; i <= (int)(n); ++i)
#define revrep(i, n) for (int i = (n); i >= 0; --i)
#define pb push_back

template <class T> void chmax(T& a, const T& b) { a = max(a, b); }
template <class T> void chmin(T& a, const T& b) { a = min(a, b); }

template <class T> void uniq(T& c) { sort(c.begin(), c.end()); c.erase(unique(c.begin(), c.end()), c.end()); }
 
template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
template <class T> T to_T(const string& s) { istringstream is(s); T res; is >> res; return res; }
  
template <class T, class U> ostream& operator<<(ostream& os, pair<T, U>& p) { os << "( " << p.first << ", " << p.second << " )"; return os; }
  
template <class T> void print(T a, int n, const string& deli = " ", int br = 1) { for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } while (br--) cout << endl; }
template <class T> void print(const T& c, const string& deli = " ", int br = 1) { foreach (it, c) { cout << *it; if (++it != c.end()) cout << deli;--it; } while (br--) cout << endl; }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }
   
template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

void fix_pre(int n) { cout.setf(ios::fixed, ios::floatfield); cout.precision(10); }
void fast_io() { cin.tie(0); ios::sync_with_stdio(false); }
#define trace(x) (cout << #x << ": " << (x) << endl)
 
bool in_rect(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }


typedef long long ll;
typedef pair<int, int> pint;
 
// y(v): v>^<  y(^): ^>v<
const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };

const double PI = acos(-1.0);



class SCC
{
private:
    vector<int> vs;	// 帰りの順番, 後ろのほう要素は始点側
    vector<bool> used;

    void dfs(int v)
    {
        used[v] = true;
        for (int i = 0; i < (int)g[v].size(); ++i)
            if (!used[g[v][i]])
                dfs(g[v][i]);
        vs.push_back(v);
    }

    void rdfs(int v, int k)
    {
        used[v] = true;
        component[v] = k;
        for (int i = 0; i < (int)rg[v].size(); ++i)
            if (!used[rg[v][i]])
                rdfs(rg[v][i], k);
    }

public:
    int V;
    vector<vector<int> > g;
    vector<vector<int> > rg;
    vector<int> component;
    int num_components;

    SCC(int V)
        : vs(V), used(V), V(V), g(V), rg(V), component(V), num_components(-1) { }

    void add_edge(int from, int to)
    {
        g[from].push_back(to);
        rg[to].push_back(from);
    }

    // 強連結成分の数を返す
    // O(V + E)
    // グラフの始点側の値(component[v])は小さい
    // 末端は大きい値, 最末端(component[v] == scc() - 1)
    int scc()
    {
        vs.clear();
        fill(used.begin(), used.end(), false);
        for (int i = 0; i < V; ++i)
            if (!used[i])
                dfs(i);

        fill(used.begin(), used.end(), false);
        int k = 0;
        for (int i = vs.size() - 1; i >= 0; --i)
            if (!used[vs[i]])
                rdfs(vs[i], k++);
        return num_components = k;
    }

    // scc_g: graph by components, nodes: the numbers of original graph
    void build_graph(vector<vector<int> >& scc_g, vector<vector<int> >& original_nodes)
    {
        if (num_components == -1)
            scc();

        scc_g.clear();
        scc_g.resize(num_components);
        original_nodes.clear();
        original_nodes.resize(num_components);


        for (int i = 0; i < V; ++i)
            original_nodes[component[i]].push_back(i);

        for (int i = 0; i < V; ++i)
            for (int j = 0; j < (int)g[i].size(); ++j)
                scc_g[component[i]].push_back(component[g[i][j]]);
        // remove duplicated edges (O(ElogE)... decrease complexity???)
        for (int i = 0; i < num_components; ++i)
        {
            sort(scc_g[i].begin(), scc_g[i].end());
            scc_g[i].erase(unique(scc_g[i].begin(), scc_g[i].end()), scc_g[i].end());
        }
    }
};


void input_graph(vector<vector<int> >& scc_g, vector<string>& chars)
{
    int n, m;
    char c[111];
    cin >> n >> m;
    input(c, n);

    SCC scc(n);
    rep(i, m)
    {
        int a, b;
        cin >> a >> b;
        --a, --b;
        scc.add_edge(a, b);
    }

    vector<vector<int> > nodes;
    scc.build_graph(scc_g, nodes);

    chars.resize(nodes.size());
    rep(i, nodes.size())
    {
        rep(j, nodes[i].size())
            chars[i] += c[nodes[i][j]];
        sort(all(chars[i]));
    }
}
int main()
{
    vector<vector<int> > aki_g, maki_g;
    vector<string> aki_c, maki_c;
    input_graph(aki_g, aki_c);
    input_graph(maki_g, maki_c);
    const int n = aki_g.size(), m = maki_g.size();

    int score[111][111];
    rep(i, n) rep(j, m)
    {
        score[i][j] = 0;
        rep(k, aki_c[i].size())
            score[i][j] |= binary_search(all(maki_c[j]), aki_c[i][k]);
        if (score[i][j] > 0 && aki_c[i].size() >= 2 && maki_c[j].size() >= 2)
        {
            // found loop
            cout << -1 << endl;
            return 0;
        }
    }

    int dp[111][111];
    CL(dp, 0);
    rep(i, n) rep(j, m)
    {
        dp[i][j] += score[i][j];

        static vector<int> ni, nj;
        ni.clear(), nj.clear();

        if (score[i][j] == 0)
            ni.pb(i);
        rep(k, aki_g[i].size())
            ni.pb(aki_g[i][k]);

        if (score[i][j] == 0)
            nj.pb(j);
        rep(k, maki_g[j].size())
            nj.pb(maki_g[j][k]);

        rep(p, ni.size()) rep(q, nj.size())
            chmax(dp[ni[p]][nj[q]], dp[i][j]);
    }

    int res = 0;
    rep(i, n) rep(j, m)
        chmax(res, dp[i][j]);
    cout << res << endl;
}

Measured memory_bytes: 1484