package net.ipipip0129.yukicoder.no762;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) throws IOException {
        // 入力が多いときはこれを使う。(Scanner はなじみ深いが遅い)
        // reader.readLine()　これで一行を取得する。
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        String[] split_str = reader.readLine().split(" ");
        int leaf_num = Integer.parseInt(split_str[0]);
        int pass_num = Integer.parseInt(split_str[1]);

        PDCALeaf[] pdcaLeaves = new PDCALeaf[leaf_num];

        String pdca_str = reader.readLine();

        // 頂点の構築
        for (int i = 0; i < leaf_num; i++) {
            switch (pdca_str.charAt(i)) {
                case 'P':
                    pdcaLeaves[i] = new PDCALeaf(PDCA.Plan, -1);
                    break;
                case 'D':
                    pdcaLeaves[i] = new PDCALeaf(PDCA.Do, -1);
                    break;
                case 'C':
                    pdcaLeaves[i] = new PDCALeaf(PDCA.Check, -1);
                    break;
                case 'A':
                    pdcaLeaves[i] = new PDCALeaf(PDCA.Act, 1);
                    break;
            }
        }

        // パスの構築
        for (int i = 0; i < pass_num; i++) {
            split_str = reader.readLine().split(" ");
            int a_num = Integer.parseInt(split_str[0]) - 1;
            int b_num = Integer.parseInt(split_str[1]) - 1;
            PDCA a_type = pdcaLeaves[a_num].getType();
            PDCA b_type = pdcaLeaves[b_num].getType();

            if ((a_type == PDCA.Act && b_type == PDCA.Check) ||
                    (a_type == PDCA.Check && b_type == PDCA.Do) ||
                    (a_type == PDCA.Do && b_type == PDCA.Plan)) {
                pdcaLeaves[b_num].addLeaf(a_num);
            } else if ((a_type == PDCA.Check && b_type == PDCA.Act) ||
                    (a_type == PDCA.Do && b_type == PDCA.Check) ||
                    (a_type == PDCA.Plan && b_type == PDCA.Do)) {
                pdcaLeaves[a_num].addLeaf(b_num);
            }
        }

        long ans = 0;

        // パスの集計
        for (int i = 0; i < leaf_num; i++) {
            if (pdcaLeaves[i].getType() == PDCA.Plan) {
                ans += getWeight(pdcaLeaves, i);
            }
        }

        System.out.println(ans % 1000000007);

        reader.close();
    }

    static long getWeight(PDCALeaf[] leaves, int leaf) {
        if (0 <= leaves[leaf].getWeight()) {
            return leaves[leaf].getWeight();
        } else {
            int weight = 0;
            for (int l : leaves[leaf].getLeaf_list()) {
                weight += getWeight(leaves, l);
            }

            leaves[leaf].setWeight(weight);
            return weight;
        }
    }
}

class PDCALeaf {

    PDCA type_pdca;
    long weight;
    List<Integer> leaf_list;

    PDCALeaf(PDCA type, int weight) {
        this.type_pdca = type;
        this.weight = weight;
        this.leaf_list = new ArrayList<>();
    }

    void addLeaf(int leaf_num) {
        leaf_list.add(leaf_num);
    }

    PDCA getType() {
        return type_pdca;
    }

    List<Integer> getLeaf_list() {
        return leaf_list;
    }

    long getWeight() {
        return weight;
    }

    public void setWeight(long weight) {
        this.weight = weight;
    }
}

enum PDCA {
    Plan,
    Do,
    Check,
    Act
}