import sys
sys.setrecursionlimit(10**6)

v_count, edge_count = map(int, input().split())
S = input()
edges = [[] for _ in [0]*v_count]
next_c = {"P":"D", "D":"C", "C":"A", "A":""}
mod = 10**9+7

for u, v in (map(int, l.split()) for l in sys.stdin):
    edges[u-1].append(v-1)
    edges[v-1].append(u-1)

dp = [-1]*v_count

def rec(v, c):
    if dp[v] == -1:
        _c = next_c[c]
        dp[v] = sum(rec(dest, _c)for dest in edges[v] if S[dest] == c) % mod
    return dp[v]


a_index = S.find("A")
while a_index != -1:
    dp[a_index] = 1
    a_index = S.find("A", a_index+1)

ans = 0
p_index = S.find("P")
while p_index != -1:
    ans += rec(p_index, "D")
    p_index = S.find("P", p_index+1)

print(ans % mod)