import cmath
import sys
from collections import deque, defaultdict
from heapq import heappop,heappush
from copy import deepcopy

INF=10**18
MOD=10**9+7
MAX=10**5+7


g=[[] for i in range(MAX)]
mem=[-1]*MAX

def rec(u):
  global s, g, mem

  if s[u]==3: return 1
  if mem[u]!=-1: return mem[u]

  res=0
  for v in g[u]:
    if s[u]+1==s[v]:
      res+=rec(v)
      res%=MOD

  mem[u]=res
  return res


def main():
  global s, g

  N,M=map(int, input().split())

  d={'P':0, 'D':1, 'C':2, 'A':3}

  s=input()
  s=list(map(lambda c: d[c], s))

  for i in range(M):
    u,v=map(int, input().split())
    u-=1
    v-=1

    if s[u]+1==s[v]: g[u].append(v)
    if s[v]+1==s[u]: g[v].append(u)

  ans=0
  for i in range(N):
    if s[i]==0:
      ans+=rec(i)
      ans%=MOD
  print(ans)


if __name__=='__main__':
    main()