#include <iostream>
#include <vector>
#include <string>

template <class Cost = int>
struct Edge {
    int src, dst;
    Cost cost;
    Edge(int src = -1, int dst = -1, Cost cost = 1)
        : src(src), dst(dst), cost(cost){};

    bool operator<(const Edge<Cost>& e) const { return this->cost < e.cost; }
    bool operator>(const Edge<Cost>& e) const { return this->cost > e.cost; }
};

template <class Cost = int>
using Graph = std::vector<std::vector<Edge<Cost>>>;

constexpr int MOD = 1000000007;

void solve() {
    int n, m;
    std::string s;
    std::cin >> n >> m >> s;

    Graph<> graph(n);
    while (m--) {
        int u, v;
        std::cin >> u >> v;

        --u, --v;
        graph[u].emplace_back(u, v);
        graph[v].emplace_back(v, u);
    }

    std::vector<int> dp(n, 0);
    for (int v = 0; v < n; ++v) {
        if (s[v] == 'P') dp[v] = 1;
    }

    auto ndp = dp;
    for (char c : std::string("DCA")) {
        std::fill(ndp.begin(), ndp.end(), 0);

        for (int v = 0; v < n; ++v) {
            if (s[v] != c) continue;

            for (auto e : graph[v]) {
                (ndp[v] += dp[e.dst]) %= MOD;
            }
        }

        std::swap(dp, ndp);
    }

    int ans = 0;
    for (auto x : dp) (ans += x) %= MOD;

    std::cout << ans << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}