ll n,r,u[2d5];set<ll>v[2d5];ll f(ll j,ll p){ll a=1;for(ll x:v[j])a&=x-p?f(x,j):1;r+=a;return!a;}{rd(n,u(n*2-2));rep(i,n*2-2)v[u[i]].insert(u[i^1]);f(1,1);wt(r);}