#include <bits/stdc++.h>

constexpr int N = 15;

int main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);
    int n, m, k;
    std::cin >> n >> m >> k;
    std::vector<int> a(k);
    for (auto &x : a) std::cin >> x, --x;
    std::vector<std::vector<int>> g(n);
    for (int i = 0; i < m; ++i) {
        int u, v;
        std::cin >> u >> v, --u, --v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    int dp[N][1 << N][N]{};
    for (int i = 0; i < k; ++i)
        dp[i][1 << a[i]][a[i]] = 1;
    for (int i = 0; i < k; ++i)
        for (unsigned mask = 0; mask < (1u << n); ++mask)
            for (int j = 0; j < n; ++j) if (dp[i][mask][j])
                for (auto &nj : g[j]) if (~mask >> nj & 1)
                    dp[i][mask | 1 << nj][nj] = 1;
    int turn[N + 1][N]{};
    for (int i = 0; i < k; ++i)
        for (unsigned mask = 0; mask < (1u << n); ++mask)
            for (int j = 0; j < n; ++j) if (dp[i][mask][j])
                turn[__builtin_popcount(mask)][j] |= 1 << i;
    int res = 0;
    for (int step = 0; step <= n; ++step)
        for (int i = 0; i < n; ++i)
            if (turn[step][i] == (1 << k) - 1) {
                std::cout << i + 1 << '\n';
                return 0;
            }
    std::cout << -1 << '\n';
    return 0;
}