#include using namespace std; using uint = unsigned int; using ll = long long; using ull = unsigned long long; using pii = pair; using pll = pair; template using vec = vector; template using vvec = vector>; #define rep(i, n) for (int i = 0; i < (n); i++) #define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--) #define all(x) begin(x), end(x) constexpr char ln = '\n'; template inline int SZ(const Container& v) { return int(v.size()); } template inline void UNIQUE(vector& v) { v.erase(unique(v.begin(), v.end()), v.end()); } template inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; } inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); } inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); } inline int popcount(ull x) { return __builtin_popcountll(x); } inline int kthbit(ull x, int k) { return (x >> k) & 1; } inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; } const string YESNO[2] = {"NO", "YES"}; const string YesNo[2] = {"No", "Yes"}; inline void YES(bool t = true) { cout << YESNO[t] << "\n"; } inline void Yes(bool t = true) { cout << YesNo[t] << "\n"; } template inline void drop(T x) { cout << x << "\n"; exit(0); } inline void print() { cout << "\n"; } template inline void print(const vector& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); } template inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); } #ifdef MINATO_LOCAL template ostream& operator<<(ostream& os, pair p) { return os << "(" << p.first << ", " << p.second << ")"; } template void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; } template void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get(t); debug_tuple(os, t); } template ostream& operator<<(ostream& os, tuple t) { os << "("; debug_tuple<0, tuple, Args...>(os, t); return os << ")"; } string debug_delim(int& i) { return i++ == 0 ? "" : ", "; } #define debug_embrace(x) { int i = 0; os << "{"; { x } return os << "}"; } template ostream& operator<<(ostream& os, vector v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, array a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template enable_if_t>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, set s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, map mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, multiset s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) } template ostream& operator<<(ostream& os, deque q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, priority_queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } template ostream& operator<<(ostream& os, priority_queue, greater> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } void debug_out() { cerr << endl; } template void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); } #define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__) #else #define debug(...) (void(0)) #endif struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_; /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// template struct SegmentTree { private: F op; T e; int _n, size ,log; vector node; public: SegmentTree() {} SegmentTree(const F& op, T e, int n) : SegmentTree(op, e, vector(n, e)) {} SegmentTree(const F& op, T e, const vector& v) : op(op), e(e), _n(int(v.size())), log(0) { while ((1< (2 * size, e); for (int i = 0; i < _n; i++) node[size + i] = v[i]; for (int i = size - 1; i >= 1; i--) { update(i); } } // (0-indexed) void set(int p, T x) { assert(0 <= p && p < _n); p += size; node[p] = x; for (int i = 1; i <= log; i++) update(p >> i); } // [l, r) (0-indexed) T get(int l, int r) { if (l >= r) return e; T resl = e, resr = e; l += size; r += size; while (l < r) { if (l & 1) resl = op(resl, node[l++]); l >>= 1; if (r & 1) resr = op(node[--r], resr); r >>= 1; } return op(resl, resr); } T all_get() { return node[1]; } template int max_right(int l, const C& check) { assert(0 <= l && l <= _n); assert(check(e)); if (l == _n) return _n; l += size; T sm = e; do { while (~l & 1) l >>= 1; if (!check(op(sm, node[l]))) { while (l < size) { l = (2 * l); if (check(op(sm, node[l]))) { sm = op(sm, node[l]); l++; } } return l - size; } sm = op(sm, node[l]); l++; } while ((l & -l) != l); return _n; } template int min_left(int r, const C& check) { assert(0 <= r && r <= _n); assert(check(e)); if (r == 0) return 0; r += size; T sm = e; do { r--; while (r > 1 && (r & 1)) r >>= 1; if (!check(op(node[r], sm))) { while (r < size) { r = (2 * r + 1); if (check(op(node[r], sm))) { sm = op(node[r], sm); r--; } } return r + 1 - size; } sm = op(node[r], sm); } while ((r & -r) != r); return 0; } T operator[](int p) { assert(0 <= p && p < _n); return node[p + size]; } private: void update(int k) { node[k] = op(node[2 * k], node[2 * k + 1]); } }; template struct Compress { public: Compress() {} Compress(const vector& vs) { add(vs); } Compress(const initializer_list>& vs) { for (T& e : vs) add(e); } void add(const vector& vs) { copy(vs.begin(), vs.end(), back_inserter(xs)); } void add(const T& x) { xs.emplace_back(x); } int build() { sort(xs.begin(), xs.end()); xs.erase(unique(xs.begin(), xs.end()), xs.end()); return int(xs.size()); } int size() const { return int(xs.size()); } vector get(const vector& vs) const { vector ret; ret.reserve(vs.size()); transform(vs.begin(), vs.end(), back_inserter(ret), [&](const T& e) { return lower_bound(xs.begin(), xs.end(), e) - xs.begin(); }); return ret; } int get(const T& x) const { return lower_bound(xs.begin(), xs.end(), x) - xs.begin(); } const T& operator[](int k) const { return xs[k]; } private: vector xs; }; constexpr int MAX = TEN(9) + 1; int main() { int N; cin >> N; vec A((N+1)*2,MAX); rep(i,N) { cin >> A[i]; A[i+N+1] = A[i]; } debug(A); Compress Com(A); Com.build(); auto CA = Com.get(A); auto f=[](int a, int b) { return min(a, b); }; const int e = TEN(9); SegmentTree seg(f,e,CA); int ans = 0; set dic; rep(i,N) { auto check=[&](int val) { return val >= CA[i]+2; }; int r = seg.max_right(i+1,check); if (CA[r]!=CA[i]) ans++; if (CA[r]==CA[i]+1) dic.insert(CA[i]); } cout << ans - SZ(dic) << ln; }