#define MOD_TYPE 2 #include using namespace std; //#include #include //#include using namespace atcoder; #if 0 #include #include using Int = boost::multiprecision::cpp_int; using lld = boost::multiprecision::cpp_dec_float_100; #endif #if 0 #include #include #include #include using namespace __gnu_pbds; using namespace __gnu_cxx; template using extset = tree, rb_tree_tag, tree_order_statistics_node_update>; #endif #if 1 #pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #endif #pragma region Macros using ll = long long int; using ld = long double; using pii = pair; using pll = pair; using pld = pair; template using smaller_queue = priority_queue, greater>; #if MOD_TYPE == 1 constexpr ll MOD = ll(1e9 + 7); #else #if MOD_TYPE == 2 constexpr ll MOD = 998244353; #else constexpr ll MOD = 1000003; #endif #endif using mint = static_modint; constexpr int INF = (int)1e9 + 10; constexpr ll LINF = (ll)4e18; constexpr double PI = acos(-1.0); constexpr double EPS = 1e-11; constexpr int Dx[] = {0, 0, -1, 1, -1, 1, -1, 1, 0}; constexpr int Dy[] = {1, -1, 0, 0, -1, -1, 1, 1, 0}; #define REP(i, m, n) for (ll i = m; i < (ll)(n); ++i) #define rep(i, n) REP(i, 0, n) #define REPI(i, m, n) for (int i = m; i < (int)(n); ++i) #define repi(i, n) REPI(i, 0, n) #define MP make_pair #define MT make_tuple #define YES(n) cout << ((n) ? "YES" : "NO") << "\n" #define Yes(n) cout << ((n) ? "Yes" : "No") << "\n" #define possible(n) cout << ((n) ? "possible" : "impossible") << "\n" #define Possible(n) cout << ((n) ? "Possible" : "Impossible") << "\n" #define Yay(n) cout << ((n) ? "Yay!" : ":(") << "\n" #define all(v) v.begin(), v.end() #define NP(v) next_permutation(all(v)) #define dbg(x) cerr << #x << ":" << x << "\n"; #define UNIQUE(v) v.erase(unique(all(v)), v.end()) struct io_init { io_init() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << setprecision(30) << setiosflags(ios::fixed); }; } io_init; template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } inline ll CEIL(ll a, ll b) { return (a + b - 1) / b; } template inline void Fill(A (&array)[N], const T& val) { fill((T*)array, (T*)(array + N), val); } template vector compress(vector& v) { vector val = v; sort(all(val)), val.erase(unique(all(val)), val.end()); for (auto&& vi : v) vi = lower_bound(all(val), vi) - val.begin(); return val; } template constexpr istream& operator>>(istream& is, pair& p) noexcept { is >> p.first >> p.second; return is; } template constexpr ostream& operator<<(ostream& os, pair p) noexcept { os << p.first << " " << p.second; return os; } ostream& operator<<(ostream& os, mint m) { os << m.val(); return os; } ostream& operator<<(ostream& os, modint m) { os << m.val(); return os; } random_device seed_gen; mt19937_64 engine(seed_gen()); struct BiCoef { vector fact_, inv_, finv_; BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) { fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1); for (int i = 2; i < n; i++) { fact_[i] = fact_[i - 1] * i; inv_[i] = -inv_[MOD % i] * (MOD / i); finv_[i] = finv_[i - 1] * inv_[i]; } } mint c(ll n, ll k) const noexcept { if (n < k || n < 0 || k < 0) return 0; return fact_[n] * finv_[k] * finv_[n - k]; } mint P(ll n, ll k) const noexcept { return c(n, k) * fact_[k]; } mint H(ll n, ll k) const noexcept { return c(n + k - 1, k); } mint Ch1(ll n, ll k) const noexcept { if (n < 0 || k < 0) return 0; mint res = 0; for (int i = 0; i < n; i++) res += c(n, i) * mint(n - i).pow(k) * (i & 1 ? -1 : 1); return res; } mint fact(ll n) const noexcept { if (n < 0) return 0; return fact_[n]; } mint inv(ll n) const noexcept { if (n < 0) return 0; return inv_[n]; } mint finv(ll n) const noexcept { if (n < 0) return 0; return finv_[n]; } }; BiCoef bc(500010); #pragma endregion void solve() { int n, d; cin >> n >> d; vector p(n), q(n); rep(i, n) cin >> p[i] >> q[i]; ll Max = -LINF; auto itr = min_element(all(p)); ll pmin = *itr; int pmin_i = itr - p.begin(); ll pmin2 = LINF; int pmin_i2; rep(i, n) { if (i == pmin_i) continue; if (chmin(pmin2, p[i])) pmin_i2 = i; } bool pass = false; if (pmin == pmin2 and (p[pmin_i] <= q[pmin_i] or p[pmin_i2] <= q[pmin_i2])) pass = true; rep(i, n) rep(j, n) { if (i == j) continue; ll Min = 0; if (d % 2 == 0) { chmin(Min, -p[i]); if (d > 2) chmin(Min, -p[i] + q[i] - p[j]); ll s = -p[i] + q[i] - p[j] + q[j]; if (pass) { chmin(Min, s * (d / 2 - 1) - pmin); } else { chmin(Min, s * (d / 2 - 1) - p[i]); if (pmin_i != i) chmin(Min, s * (d / 2 - 1) - p[i] + q[i] - pmin); else chmin(Min, s * (d / 2 - 1) - p[i] + q[i] - pmin2); } } else { chmin(Min, -p[i]); chmin(Min, -p[i] + q[i] - p[j]); ll s = -p[i] + q[i] - p[j] + q[j]; chmin(Min, s * ((d - 1) / 2 - 1) - p[i]); chmin(Min, s * ((d - 1) / 2 - 1) - p[i] + q[i] - p[j]); if (pmin_i != j) chmin(Min, s * ((d - 1) / 2 - 1) - p[i] + q[i] - p[j] + q[j] - pmin); else chmin(Min, s * ((d - 1) / 2 - 1) - p[i] + q[i] - p[j] + q[j] - pmin2); } chmax(Max, Min); } cout << Max << "\n"; } int main() { solve(); }