#pragma GCC optimize("fast-math") #include using namespace std; using ll = long long; using ld = long double; using ull = unsigned long long; using uint = unsigned; using pcc = pair; using pii = pair; using pll = pair; using pdd = pair; using tuplis = array; template using pq = priority_queue, greater>; const ll LINF=0x1fffffffffffffff; const ll MINF=0x7fffffffffff; const int INF=0x3fffffff; const int MOD=1000000007; const int MODD=998244353; const ld DINF=numeric_limits::infinity(); const ld EPS=1e-9; const ld PI=3.1415926535897932; const ll dx[] = {0, 1, 0, -1, 1, -1, 1, -1}; const ll dy[] = {1, 0, -1, 0, 1, 1, -1, -1}; #define overload5(a,b,c,d,e,name,...) name #define overload4(a,b,c,d,name,...) name #define overload3(a,b,c,name,...) name #define rep1(n) for(ll i=0;i(a);) #define rrep4(i,a,b,c) for(ll i=(a)+((b)-(a)-1)/(c)*(c);i>=(a);i-=c) #define rrep(...) overload4(__VA_ARGS__,rrep4,rrep3,rrep2,rrep1)(__VA_ARGS__) #define each1(i,a) for(auto&&i:a) #define each2(x,y,a) for(auto&&[x,y]:a) #define each3(x,y,z,a) for(auto&&[x,y,z]:a) #define each4(w,x,y,z,a) for(auto&&[w,x,y,z]:a) #define each(...) overload5(__VA_ARGS__,each4,each3,each2,each1)(__VA_ARGS__) #define all1(i) begin(i),end(i) #define all2(i,a) begin(i),begin(i)+a #define all3(i,a,b) begin(i)+a,begin(i)+b #define all(...) overload3(__VA_ARGS__,all3,all2,all1)(__VA_ARGS__) #define rall1(i) (i).rbegin(),(i).rend() #define rall2(i,k) (i).rbegin(),(i).rbegin()+k #define rall3(i,a,b) (i).rbegin()+a,(i).rbegin()+b #define rall(...) overload3(__VA_ARGS__,rall3,rall2,rall1)(__VA_ARGS__) #define sum(...) accumulate(all(__VA_ARGS__),0LL) #define dsum(...) accumulate(all(__VA_ARGS__),0.0L) #define Msum(...) accumulate(all(__VA_ARGS__),Modint{0}) #define elif else if #define INT(...) int __VA_ARGS__;in(__VA_ARGS__) #define LL(...) ll __VA_ARGS__;in(__VA_ARGS__) #define ULL(...) ull __VA_ARGS__;in(__VA_ARGS__) #define STR(...) string __VA_ARGS__;in(__VA_ARGS__) #define CHR(...) char __VA_ARGS__;in(__VA_ARGS__) #define DBL(...) double __VA_ARGS__;in(__VA_ARGS__) #define LD(...) ld __VA_ARGS__;in(__VA_ARGS__) #define Sort(a) sort(all(a)) #define Rev(a) reverse(all(a)) #define Uniq(a) sort(all(a));a.erase(unique(all(a)),end(a)) #define vec(type,name,...) vectorname(__VA_ARGS__) #define VEC(type,name,size) vectorname(size);in(name) #define vv(type,name,h,...) vector name(h,vector(__VA_ARGS__)) #define VV(type,name,h,w) vector name(h,vector(w));in(name) #define vvv(type,name,h,w,...) vector name(h,vector(w,vector(__VA_ARGS__))) template auto min(const T& a){ return *min_element(all(a)); } template auto max(const T& a){ return *max_element(all(a)); } template auto count(const T& a, const U& b){ return count(all(a), b); } template auto count_if(const T& a, U b){ return count_if(all(a), b); } template T filter(T a, U b){ a.erase(remove_if(all(a), not_fn(b)), a.end()); return a; } inline ll popcnt(ull a){ return __builtin_popcountll(a); } ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; } ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; } template bool chmin(T& a, const T& b){ if(a > b){ a = b; return 1; } return 0; } template bool chmax(T& a, const T& b){ if(a < b){ a = b; return 1; } return 0; } template bool chmin(T& a, const U& b){ if(a > T(b)){ a = b; return 1; } return 0; } template bool chmax(T& a, const U& b){ if(a < T(b)){ a = b; return 1; } return 0; } vector iota(ll n, ll begin = 0){ vector a(n); iota(a.begin(), a.end(), begin); return a; } vector factor(ull x){ vector ans; for(ull i = 2; i * i <= x; i++) if(x % i == 0){ ans.push_back({i, 1}); while((x /= i) % i == 0) ans.back().second++; } if(x != 1) ans.push_back({x, 1}); return ans; } vector divisor(ull x){ vector ans; for(ull i = 1; i * i <= x; i++) if(x % i == 0) ans.push_back(i); rrep(ans.size() - (ans.back() * ans.back() == x)) ans.push_back(x / ans[i]); return ans; } template unordered_map press(vector a){ Uniq(a); unordered_map ans; rep(a.size()) ans[a[i]] = i; return ans; } template auto run_press(const T& a){ vector, ll>> ans; each(x, a){ if(ans.empty() || ans.back().first != x) ans.emplace_back(x, 1); else ans.back().second++; } return ans; } template void in(Ts&... t); [[maybe_unused]] void print(){} template void print(const T& t, const Ts&... ts); template void out(const Ts&... ts){ print(ts...); cout << '\n'; } namespace IO{ #define VOID(a) decltype(void(a)) struct setting{ setting(){ cin.tie(nullptr); ios::sync_with_stdio(false); fixed(cout); cout.precision(12); } } setting; template struct P : P{}; template<> struct P<0>{}; template void i(T& t){ i(t, P<3>{}); } void i(vector::reference t, P<3>){ int a; i(a); t = a; } template auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; } template auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); } template void ituple(T& t, index_sequence){ in(get(t)...); } template auto i(T& t, P<0>) -> VOID(tuple_size{}){ ituple(t, make_index_sequence::value>{}); } template void o(const T& t){ o(t, P<4>{}); } template void o(const char (&t)[N], P<4>){ cout << t; } template void o(const T (&t)[N], P<3>){ o(t[0]); for(size_t i = 1; i < N; i++){ o(' '); o(t[i]); } } template auto o(const T& t, P<2>) -> VOID(cout << t){ cout << t; } template auto o(const T& t, P<1>) -> VOID(begin(t)){ bool first = 1; for(auto&& x : t) { if(first) first = 0; else o(' '); o(x); } } template void otuple(const T& t, index_sequence){ print(get(t)...); } template auto o(T& t, P<0>) -> VOID(tuple_size{}){ otuple(t, make_index_sequence::value>{}); } #undef VOID } #define unpack(a) (void)initializer_list{(a, 0)...} template void in(Ts&... t){ unpack(IO::i(t)); } template void print(const T& t, const Ts&... ts){ IO::o(t); unpack(IO::o((cout << ' ', ts))); } #undef unpack #ifdef DEBUG inline ll __lg(ull x){ return 63 - __builtin_clzll(x); } #define debug(...) { print(#__VA_ARGS__); print(":"); out(__VA_ARGS__); } #else #define debug(...) void(0) #endif void first(bool i = true){ return out(i?"first":"second"); } void First(bool i = true){ return out(i?"First":"Second"); } void Yes(bool i = true){ return out(i?"Yes":"No"); } void No(){ return out("No"); } void YES(bool i = true){ return out(i?"YES":"NO"); } void NO(){ return out("NO"); } void Yay(bool i = true){ return out(i?"Yay!":":("); } void possible(bool i = true){ return out(i?"possible":"impossible"); } void Possible(bool i = true){ return out(i?"Possible":"Impossible"); } void POSSIBLE(bool i = true){ return out(i?"POSSIBLE":"IMPOSSIBLE"); } void Case(ll i){ printf("Case #%lld: ", i); } int main(){ LL(n); VEC(ll,a,n); ll ans=0,up=0; rep(n-1){ if(a[i]==a[i+1]){ up=0; } elif(a[i]