// An AC a day keeps the doctor away. #include using namespace std; /*{{{*/ #define all(x) begin(x), end(x) #ifdef CKISEKI #include #define safe cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n" #define debug(a...) debug_(#a, a) #define orange(a...) orange_(#a, a) void debug_(auto s, auto ...a) { cerr << "\e[1;32m(" << s << ") = ("; int f = 0; (..., (cerr << (f++ ? ", " : "") << a)); cerr << ")\e[0m\n"; } void orange_(auto s, auto L, auto R) { cerr << "\e[1;33m[ " << s << " ] = [ "; using namespace experimental; copy(L, R, make_ostream_joiner(cerr, ", ")); cerr << " ]\e[0m\n"; } #else #define safe ((void)0) #define debug(...) safe #define orange(...) safe #endif template class Modular { public: constexpr Modular() : v() {} template Modular(const U &u) { v = (0 <= u && u < MOD ? u : (u%MOD+MOD)%MOD); } template explicit operator U() const { return U(v); } T operator()() const { return v; } #define REFOP(type, expr...) Modular &operator type (const Modular &rhs) { return expr, *this; } REFOP(+=, v += rhs.v - MOD, v += MOD & (v >> width)) ; REFOP(-=, v -= rhs.v, v += MOD & (v >> width)) // fits for MOD^2 <= 9e18 REFOP(*=, v = static_cast(1LL * v * rhs.v % MOD)) ; REFOP(/=, *this *= inverse(rhs.v)) #define VALOP(op) friend Modular operator op (Modular a, const Modular &b) { return a op##= b; } VALOP(+) ; VALOP(-) ; VALOP(*) ; VALOP(/) Modular operator-() const { return 0 - *this; } friend bool operator == (const Modular &lhs, const Modular &rhs) { return lhs.v == rhs.v; } friend bool operator != (const Modular &lhs, const Modular &rhs) { return lhs.v != rhs.v; } friend std::istream & operator>>(std::istream &I, Modular &m) { T x; I >> x, m = x; return I; } friend std::ostream & operator<<(std::ostream &O, const Modular &m) { return O << m.v; } private: constexpr static int width = sizeof(T) * 8 - 1; T v; static T inverse(T a) { // copy from tourist's template T u = 0, v = 1, m = MOD; while (a != 0) { T t = m / a; m -= t * a; std::swap(a, m); u -= t * v; std::swap(u, v); } assert(m == 1); return u; } }; using lld = int64_t; using llf = long double; template using max_heap = std::priority_queue,less >; template using min_heap = std::priority_queue,greater >; template int get_pos(const V &v, T x) { return lower_bound(all(v),x) - begin(v); } template void sort_uni(V &v) { sort(all(v)), v.erase(unique(all(v)),end(v)); } template bool chmin(T &x, const T &v) { return v < x ? (x=v, true) : false; } template bool chmax(T &x, const T &v) { return x < v ? (x=v, true) : false; } constexpr inline lld cdiv(lld x, lld m) { return x/m + (x%m ? (x<0) ^ (m>0) : 0); } // ceiling divide constexpr inline lld modpow(lld e,lld p,lld m) { lld r=1; for(e%=m;p;p>>=1,e=e*e%m) if(p&1) r=r*e%m; return r; }/*}}}*/ constexpr llf eps = 1e-9; constexpr lld maxn = 200025, INF = 1e18, mod = 998244353, K = 14699, inf = 1e9; using Mint = Modular; Mint modpow(Mint e, uint64_t p) { Mint r = 1; while (p) (p&1) && (r *= e), e *= e, p >>= 1; return r; } // 0^0 = 1 const auto dummy = [] { return cin.tie(nullptr)->sync_with_stdio(false); }(); signed main() { int N; cin >> N; vector> g(N); for (int i = 1; i < N; i++) { int u, v; cin >> u >> v; --u, --v; g[u].emplace_back(v); g[v].emplace_back(u); } vector> dp(N); auto dfs = [&](auto self, int i, int f) -> void { dp[i][1] = 1; for (int j : g[i]) if (j != f) { self(self, j, i); const auto &s = dp[j]; dp[i][0] += max(s[0], s[1]); dp[i][1] += s[0]; } }; dfs(dfs, 0, -1); int ans = inf; auto reroot = [&](auto self, int i, int f) -> void { ans = min(ans, dp[i][1]); debug(i+1, dp[i][1]); for (int j : g[i]) if (j != f) { { const auto &s = dp[j]; dp[i][0] -= max(s[0], s[1]); dp[i][1] -= s[0]; } { const auto &s = dp[i]; dp[j][0] += max(s[0], s[1]); dp[j][1] += s[0]; } self(self, j, i); { const auto &s = dp[i]; dp[j][0] -= max(s[0], s[1]); dp[j][1] -= s[0]; } { const auto &s = dp[j]; dp[i][0] += max(s[0], s[1]); dp[i][1] += s[0]; } } }; reroot(reroot, 0, -1); cout << ans << '\n'; }