N,M =map(int,input().split())
str =input()
pdca ={l:list() for l in ["PD","DC","CA"]}


for i in range(M):
    s,t =map(int,input().split())
    str2 =str[s-1]+str[t-1]
    if str2 =="PD":
        pdca["PD"].append([s,t])
    elif str2 =="DP":
        pdca["PD"].append([t,s])
    elif str2 =="DC":
        pdca["DC"].append([s,t])
    elif str2 =="CD":
        pdca["DC"].append([t,s])
    elif str2 =="CA":
        pdca["CA"].append([s,t])
    elif str2 =="AC":
        pdca["CA"].append([t,s])

sum = 0
dclist =[0]*N
calist =[0]*N

for lis in pdca["CA"]:
    calist[lis[0]-1] += 1
for lis in pdca["DC"]:
    dclist[lis[0]-1] += calist[lis[1]-1]
for lis in pdca["PD"]:
    sum += dclist[lis[1]-1]
print(sum)