ll n,m,r,u[2d5],v[2d5];char s[2d5];
mint w[2d5],r;
{
	rd(n,m,(s+1),(u,v)(m));
	rep(i,m){
		if(s[u[i]]=='P'&&s[v[i]]=='D')w[v[i]]+=1;
		if(s[v[i]]=='P'&&s[u[i]]=='D')w[u[i]]+=1;
	}
	rep(i,m){
		if(s[u[i]]=='D'&&s[v[i]]=='C')w[v[i]]+=w[u[i]];
		if(s[v[i]]=='D'&&s[u[i]]=='C')w[u[i]]+=w[v[i]];
	}
	rep(i,m){
		if(s[u[i]]=='C'&&s[v[i]]=='A')r+=w[u[i]];
		if(s[v[i]]=='C'&&s[u[i]]=='A')r+=w[v[i]];
	}
	wt(r);
}