#include //typedef //-------------------------#include #define M_PI 3.14159265358979323846 using namespace std; //conversion //------------------------------------------ inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; } template inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); } inline int readInt() { int x; scanf("%d", &x); return x; } //typedef //------------------------------------------ typedef vector VI; typedef vector VVI; typedef vector VS; typedef pair PII; typedef pair PLL; typedef pair TIII; typedef long long LL; typedef unsigned long long ULL; typedef vector VLL; typedef vector VVLL; //container util //------------------------------------------ #define ALL(a) (a).begin(),(a).end() #define RALL(a) (a).rbegin(), (a).rend() #define PB push_back #define MP make_pair #define SZ(a) int((a).size()) #define SQ(a) ((a)*(a)) #define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i) #define EXIST(s,e) ((s).find(e)!=(s).end()) #define SORT(c) sort((c).begin(),(c).end()) //repetition //------------------------------------------ #define FOR(i,s,n) for(int i=s;i<(int)n;++i) #define REP(i,n) FOR(i,0,n) #define MOD 1000000007 #define rep(i, a, b) for(int i = a; i < (b); ++i) #define trav(a, x) for(auto& a : x) #define all(x) x.begin(), x.end() #define sz(x) (int)(x).size() typedef long long ll; typedef pair pii; typedef vector vi; const double EPS = 1E-8; #define chmin(x,y) x=min(x,y) #define chmax(x,y) x=max(x,y) class UnionFind { public: vector par; vector siz; UnionFind(int sz_): par(sz_), siz(sz_, 1) { for (ll i = 0; i < sz_; ++i) par[i] = i; } void init(int sz_) { par.resize(sz_); siz.assign(sz_, 1LL); for (ll i = 0; i < sz_; ++i) par[i] = i; } int root(int x) { while (par[x] != x) { x = par[x] = par[par[x]]; } return x; } bool merge(int x, int y) { x = root(x); y = root(y); if (x == y) return false; if (siz[x] < siz[y]) swap(x, y); siz[x] += siz[y]; par[y] = x; return true; } bool issame(int x, int y) { return root(x) == root(y); } int size(int x) { return siz[root(x)]; } }; class WeightedUnionFind{ public: vector par; vector siz; vector diff_weight; /* 頂点間の重みの差 */ WeightedUnionFind(int sz_): par(sz_), siz(sz_, 1LL), diff_weight(sz_, 0LL){ for(int i=0; i>= 1; } return res; } #define SIEVE_SIZE 5000000+10 bool sieve[SIEVE_SIZE]; void makeSieve(){ for(int i=0; i struct LazySegmentTree { using F = function< Monoid(Monoid, Monoid) >; using G = function< Monoid(Monoid, OperatorMonoid) >; using H = function< OperatorMonoid(OperatorMonoid, OperatorMonoid) >; using P = function< OperatorMonoid(OperatorMonoid, int) >; int sz; vector< Monoid > data; vector< OperatorMonoid > lazy; const F f; const G g; const H h; const P p; const Monoid M1; const OperatorMonoid OM0; LazySegmentTree(int n, const F f, const G g, const H h, const P p, const Monoid &M1, const OperatorMonoid OM0) : f(f), g(g), h(h), p(p), M1(M1), OM0(OM0) { sz = 1; while(sz < n) sz <<= 1; data.assign(2 * sz, M1); lazy.assign(2 * sz, OM0); } void set(int k, const Monoid &x) { data[k + sz] = x; } void build() { for(int k = sz - 1; k > 0; k--) { data[k] = f(data[2 * k + 0], data[2 * k + 1]); data[k] %= MOD; } } void propagate(int k, int len) { if(lazy[k] != OM0) { if(k < sz) { lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]); lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]); } data[k] = g(data[k], p(lazy[k], len)); lazy[k] = OM0; } } Monoid update(int a, int b, const OperatorMonoid &x, int k, int l, int r) { propagate(k, r - l); if(r <= a || b <= l) { return data[k]; } else if(a <= l && r <= b) { lazy[k] = h(lazy[k], x); propagate(k, r - l); return data[k]; } else { return data[k] = f(update(a, b, x, 2 * k + 0, l, (l + r) >> 1), update(a, b, x, 2 * k + 1, (l + r) >> 1, r)); } } Monoid update(int a, int b, const OperatorMonoid &x) { return update(a, b, x, 1, 0, sz); } Monoid query(int a, int b, int k, int l, int r) { propagate(k, r - l); if(r <= a || b <= l) { return M1; } else if(a <= l && r <= b) { return data[k]; } else { return f(query(a, b, 2 * k + 0, l, (l + r) >> 1), query(a, b, 2 * k + 1, (l + r) >> 1, r)); } } Monoid query(int a, int b) { return query(a, b, 1, 0, sz); } Monoid operator[](const int &k) { return query(k, k + 1); } }; vector>> G(100010); int root = 0; int parent[25][100010]; int depth[100010]; ll arr[100010]; void dfs(int v, int prev, ll cost, int d){ arr[v] = cost; parent[0][v] = prev; depth[v] = d; for(auto u: G[v]){ if(u.first == prev) continue; dfs(u.first, v, cost + u.second, d+1); } } void init(int N){ dfs(root, -1, 0, 0); for(int k=0; k+1<25; k++){ for(int v=0; v depth[v]) swap(u, v); for(int k=0; k<25; k++){ if((depth[v]-depth[u]) >> k & 1) { v = parent[k][v]; } } if(u == v) return u; for(int k=24; k>=0; k--){ if(parent[k][u] != parent[k][v]){ u = parent[k][u]; v = parent[k][v]; } } return parent[0][u]; } int main() { cin.tie(0); ios::sync_with_stdio(false); //cout << fixed << setprecision(15); int N; cin >> N; vectorA(2*N); REP(i,2*N)cin>>A[i]; int l=0, r=2*N-1; ll ans = 0; while(l<=r){ if(A[l]-A[l+1] >= A[r]-A[r-1]){ ans += A[l]-A[l+1]; l+=2; }else{ ans += A[r]-A[r-1]; r-=2; } } cout << ans << endl; return 0; }