//#define NDEBUG #include #include #include namespace n91 { using i8 = std::int_least8_t; using i32 = std::int_least32_t; using i64 = std::int_least64_t; using u8 = std::uint_least8_t; using u32 = std::uint_least32_t; using u64 = std::uint_least64_t; using isize = std::ptrdiff_t; using usize = std::size_t; class rep { const usize f, l; public: class itr { friend rep; usize i; constexpr itr(const usize x) noexcept : i(x) {} public: void operator++() noexcept { ++i; } constexpr usize operator*() const noexcept { return i; } constexpr bool operator!=(const itr x) const noexcept { return i != x.i; } }; constexpr rep(const usize first, const usize last) noexcept : f(first), l(last) {} constexpr itr begin() const noexcept { return itr(f); } constexpr itr end() const noexcept { return itr(l); } }; class revrep { const usize f, l; public: class itr { friend revrep; usize i; constexpr itr(usize x) noexcept : i(x) {} public: void operator++() noexcept { --i; } constexpr usize operator*() const noexcept { return i; } constexpr bool operator!=(const itr x) const noexcept { return i != x.i; } }; constexpr revrep(usize first, usize last) noexcept : f(--first), l(--last) {} constexpr itr begin() const noexcept { return itr(l); } constexpr itr end() const noexcept { return itr(f); } }; template using vec_alias = std::vector; 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) { return a < b ? b - a : a - b; } } // namespace n91 #include #include #include namespace n91 { void main_() { usize n; u64 k; std::cin >> n >> k; --k; std::vector> a(n); for (auto &e : a) { std::cin >> e.first >> e.second; --e.second; } u64 le = 0, gt = 1000000000; while (gt - le != 1) { const u64 mid = (le + gt) / 2; u64 count = 0; for (const auto &e : a) { count += std::min(e.second, mid) - std::min(e.first, mid); } if (count <= k) { le = mid; } else { gt = mid; } } std::cout << le << std::endl; } } // namespace n91 int main() { n91::main_(); return 0; }