N, M = map(int, input().split())
S = input()
edge_pd, edge_dc, edge_ca = [], [], []
dp = [0] * 101010
MOD = 1000000007
for _ in range(M):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    if S[u] < S[v]:
        u, v = v, u
    ca = S[u]
    cb = S[v]
    if ca == "P" and cb == "D":
        edge_pd.append((u, v))
        dp[u] = 1
    elif ca == "D" and cb == "C":
        edge_dc.append((u, v))
    elif ca == "C" and cb == "A":
        edge_ca.append((u, v))
for u, v in edge_pd:
    dp[v] = (dp[u] + dp[v]) % MOD
for u, v in edge_dc:
    dp[v] = (dp[u] + dp[v]) % MOD
ans = 0
for u, _ in edge_ca:
    ans = (ans + dp[u]) % MOD
print(ans)