#define MD 998244353
int@n,@(a,b)--[n-1];
graph g;
g.setEdge(n,n-1,a,b);
Mint z;
rep(i,n){
	z+=Mint(2)**g.es[i];
	z-=g.es[i]==n-1?2:0;
}
wt(z);