use std::io::{Read, stdin};

fn main() {
    let mut buf = String::new();
    stdin().read_to_string(&mut buf).unwrap();
    let mut tok = buf.split_whitespace();
    let mut get = || tok.next().unwrap();
    macro_rules! get {
        ($t:ty) => (get().parse::<$t>().unwrap());
        () => (get!(usize));
    }
    let md = 1_000_000_007;
    let n = get!();
    let m = get!();
    let s = get().as_bytes();
    let mut graph = vec![vec![]; n];
    let mut count = vec![0_u64; n];
    for _ in 0..m {
        let u = get!()-1;
        let v = get!()-1;
        let gu = s[u];
        let gv = s[v];
        match (gu, gv) {
        (b'C',b'A') => count[u] += 1,
        (b'A',b'C') => count[v] += 1,
        (b'D',b'C')|(b'P',b'D') => graph[v].push(u),
        (b'C',b'D')|(b'D',b'P') => graph[u].push(v),
        _ => {},
        }
    }
    for i in 0..s.len(){
        if s[i] == b'C' {
            for &j in graph[i].iter() {
                count[j] += count[i];
                count[j] %= md;
            }
        }
    }
    for i in 0..s.len(){
        if s[i] == b'D' {
            for &j in graph[i].iter() {
                count[j] += count[i];
                count[j] %= md;
            }
        }
    }
    let mut ans = 0;
    for i in 0..s.len(){
        if s[i] == b'P' {
            ans += count[i];
            ans %= md;
        }
    }
    println!("{}", ans);
}