MOD = 10**9 + 7
N, M = gets.split.map(&:to_i)
S = gets.chomp
graph = Array.new(N) { [] }
PDCA = "PDCA"
M.times do
    (s, u), (t, v) = gets.split.map { |s| i = s.to_i - 1; [PDCA.index(S[i]), i] }.minmax
    graph[v] << u if s + 1 == t
end

vertices = Array.new(4) { [] }
N.times do |u|
    vertices[PDCA.index(S[u])] << u
end

dp = [1] * N
vertices[1, 3].each do |us|
    us.each do |u|
        dp[u] = graph[u].sum { |v| dp[v] } % MOD
    end
end

puts vertices[3].sum { |u| dp[u] } % MOD