{
	VI nodes[32];
	map<int,VI> edges;
	set<int> vis;

	ll@n,@st,@ed;
	nodes[__builtin_popcountl(st)].push_back(st);
	nodes[__builtin_popcountl(ed)].push_back(ed);
	rep(n){
		ll@s;
		nodes[__builtin_popcountl(s)].push_back(s);
	}
	rep(i,31){
		for(ll j:nodes[i]){
			for(ll k:nodes[i+1]){
				if(__builtin_popcount(j^k)==1){
					edges[j].push_back(k);
					edges[k].push_back(j);
				}
			}
		}
	}
	int q[3000];
	ll qr=0,qw=0,ans=0;
	q[qw++]=st;
	while(qr<qw){
		ll qn=qw;
		while(qr<qn){
			ll s=q[qr++];
			if(s==ed){
				wt(ans-1);
				exit(0);
			}
			for(ll j:edges[s]){
				if(vis.find(j)==vis.end()){
					vis.insert(j);
					q[qw++]=j;
				}
			}
		}
		++ans;
	}
	wt(-1);
}