ll d[61][2000];
char s[80];

{
	ll n;
	rd(s@n);

	ll a=0,b=0;
	rep(i,n){
		a+=s[i]&1;
		b+=s[i]&1?i:0;
	}

	d[0][0]=1;
	rep(i,n){
		rrep(j,1,n+1){
			rep(k,i,2000){
				d[j][k]+=d[j-1][k-i];
			}
		}
	}

	wt(d[a][b]);
}