//#define NDEBUG #include #include #include #include #include namespace n91 { using i8 = std::int_fast8_t; using i32 = std::int_fast32_t; using i64 = std::int_fast64_t; using u8 = std::uint_fast8_t; using u32 = std::uint_fast32_t; using u64 = std::uint_fast64_t; using isize = std::ptrdiff_t; using usize = std::size_t; struct rep { struct itr { usize i; constexpr itr(const usize i) noexcept : i(i) {} void operator++() noexcept { ++i; } constexpr usize operator*() const noexcept { return i; } constexpr bool operator!=(const itr x) const noexcept { return i != x.i; } }; const itr f, l; constexpr rep(const usize f, const usize l) noexcept : f(std::min(f, l)), l(l) {} constexpr auto begin() const noexcept { return f; } constexpr auto end() const noexcept { return l; } }; struct revrep { struct itr { usize i; constexpr itr(const usize i) noexcept : i(i) {} void operator++() noexcept { --i; } constexpr usize operator*() const noexcept { return i; } constexpr bool operator!=(const itr x) const noexcept { return i != x.i; } }; const itr f, l; constexpr revrep(const usize f, const usize l) noexcept : f(l - 1), l(std::min(f, l) - 1) {} constexpr auto begin() const noexcept { return f; } constexpr auto end() const noexcept { return l; } }; template auto md_vec(const usize n, const T& value) { return std::vector(n, value); } template auto md_vec(const usize n, Args... args) { return std::vector(n, md_vec(args...)); } template constexpr T difference(const T& a, const T& b) noexcept { return a < b ? b - a : a - b; } template void chmin(T& a, const T& b) noexcept { if (b < a) a = b; } template void chmax(T& a, const T& b) noexcept { if (a < b) a = b; } template T scan() { T ret; std::cin >> ret; return ret; } } // namespace n91 #include #include namespace n91 { template std::vector> run_length_encoding(const std::vector& a) { if (a.empty()) { return std::vector>(); } std::vector> ret; ret.reserve(a.size()); ret.emplace_back(a.front(), static_cast(0)); for (const T& e : a) { if (e != ret.back().first) { ret.emplace_back(e, static_cast(0)); } ++ret.back().second; } ret.shrink_to_fit(); return std::move(ret); } } // namespace n91 #include #include #include namespace n91 { void main_() { /* std::ios::sync_with_stdio(false); std::cin.tie(nullptr); //*/ const usize n = scan(); std::vector a(n); for (auto& e : a) { std::cin >> e; } usize d0 = 0, d1 = 0; for (const usize i : rep(0, n)) { const usize nd0 = (i != 0 && a[i - 1] != a[i]) ? std::max(d0, d1 + 1) : d0 + 1; const usize nd1 = d0; d0 = nd0; d1 = nd1; } std::cout << d0 << std::endl; } } // namespace n91 int main() { n91::main_(); return 0; }