#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define int long long #define ii pair #define app push_back #define all(a) a.begin(), a.end() #define bp __builtin_popcountll #define ll long long #define mp make_pair #define x first #define y second #define Time (double)clock()/CLOCKS_PER_SEC #define munq(a) sort(all(a)); a.resize(unique(all(a))-a.begin()) #define sz(a) ((int)a.size()) #ifdef LOCAL #define debug(x) do { cout << #x << ": " << x << endl; } while(0) #define debug2(x, y) do { std::cerr << #x << ", " << #y << ": " << x << ", " << y << endl; } while (0) #define debug3(x, y, z) do {std::cerr << #x << ", " << #y << ", " << #z << ": " << x << ", " << y << ", " << z << endl; } while(0) #else #define debug(x) #define debug2(x, y) #define debug3(x, y, z) #endif #define FORI(i,a,b) for (int i = (a); i < (b); ++i) #define FOR(i,a) FORI(i,0,a) #define ROFI(i,a,b) for (int i = (b)-1; i >= (a); --i) #define ROF(i,a) ROFI(i,0,a) #define rep(a) FOR(_,a) #define each(a,x) for (auto& a: x) #define FORN(i, n) FORI(i, 1, n + 1) using vi = vector; template std::istream& operator >>(std::istream& input, std::pair & data) { input >> data.x >> data.y; return input; } template std::istream& operator >>(std::istream& input, std::vector& data) { for (T& x : data) input >> x; return input; } template std::ostream& operator <<(std::ostream& output, const pair & data) { output << "(" << data.x << "," << data.y << ")"; return output; } template std::ostream& operator <<(std::ostream& output, const std::vector& data) { for (const T& x : data) output << x << " "; return output; } ll div_up(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up ll div_down(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down ll math_mod(ll a, ll b) { return a - b * div_down(a, b); } #define tcT template using V = vector; tcT> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } // set a = min(a,b) tcT> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } tcT> vector presum(vector &a) { vector p(a.size() + 1); FOR (i, a.size()) { p[i + 1] = p[i] + a[i]; } return p; } tcT> vector sufsum(vector &a) { vector p(a.size() + 1); for (int i = (int)a.size() - 1; i >= 0; --i) { p[i] = p[i + 1] + a[i]; } return p; } ll gcd(ll a, ll b) { while (b) { tie(a, b) = mp(b, a % b); } return a; } int Bit(int mask, int bit) { return (mask >> bit) & 1; } struct Line { ll k, b; Line() : k(), b() {} Line (ll _k, ll _b) : k(_k), b(_b) {} ll getVal(ll x) { return b * x + k * (x * (x - 1) / 2); } }; int intersect(Line a, Line b) { auto leftf = [&] (int l, int r, function f) { //assert(!f(l)); assert(f(r)); while (l < r - 1) { int m = (l + r) / 2; if (f(m)) { r = m; } else { l = m; } } return r; }; auto f = [&] (int x) { return a.getVal(x)<=b.getVal(x); }; return leftf(1, 3e5+7, f); } struct Hull { vector lines; vector borders; Hull() : lines(), borders() {} void addLine(Line L) { debug2(L.k,L.b); while(!lines.empty()) { debug(borders.back()); debug(lines.back().getVal(borders.back())); debug(L.getVal(borders.back())); if (lines.back().getVal(borders.back()) <= L.getVal(borders.back())) { lines.pop_back(); borders.pop_back(); } else break; } if (lines.empty()) { lines.push_back(L); borders.push_back(1LL); //leftmost query return; } if (lines.back().k == L.k) { return; } ll x = intersect(lines.back(),L); debug(x); lines.push_back(L); borders.push_back(x); } ll getMaxVal(ll x) { if (x == 0) { return 0; } int pos = upper_bound(borders.begin(), borders.end(), x) - borders.begin(); if (pos == 0) throw; pos--; //debug(pos); //debug(lines[pos].k); return lines[pos].getVal(x); } }; signed main() { #ifdef LOCAL #else #define endl '\n' ios_base::sync_with_stdio(0); cin.tie(0); #endif int n, m; cin >> n >> m; vi a(n), d(n); V l, g; priority_queue q; vi cur(n,1); FOR (i, n) { cin >> a[i] >> d[i]; if (d[i]>=0) { l.app({d[i],a[i]}); } else { int num = (int)g.size(); q.push({a[i], num}); g.app({d[i], a[i]}); } } sort(all(l)); Hull h; for (auto [k, b] : l) { h.addLine(Line(k,b)); } int ans = -1e18, gre = 0; debug(g); FOR (i, m + 1) { if (0) { for (auto [k,b] : l) { Line L = Line(k,b); ckmax(ans, gre + L.getVal(m-i)); } } else { ckmax(ans, gre + h.getMaxVal(m - i)); } gre += q.top().x; int w = q.top().y; q.pop(); cur[w]++; q.push({g[w].x*(cur[w]-1)+g[w].y,w}); } cout << ans << endl; }