N,M=map(int,input().split())
S=input()
mod=10**9+7
edegs=[]
for m in range(M):
    u,v=map(int,input().split())
    u-=1;v-=1
    edegs.append((u,v))
dp=[s=="P" for s in S]
for t in "DCA":
    prev=dp
    dp=[0]*N
    for u,v in edegs:
        dp[u]+=prev[v]
        dp[v]+=prev[u]
    for x in range(N):
        dp[x]%=mod
        if t!=S[x]:
            dp[x]=0
ans=sum(dp)%mod
print(ans)