//Proud of You// #include <bits/stdc++.h> #pragma GCC optimization ("O3") #pragma GCC optimization ("unroll-loops") using namespace std; const int N = 1e6 + 17; int n, H; struct Vector { long long x, y; Vector operator - (const Vector& other) const { return {x - other.x, y - other.y}; } long long operator * (const Vector& other) const { return x * other.y - y * other.x; } } P[N]; long long CCW(const Vector& A, const Vector& B, const Vector& C) { return ((B - A) * (C - A)); } long double getintersect(const Vector& A, const Vector& B) { return A.x - 1.0L * (A.x - B.x) / (A.y - B.y) * (A.y - H); } long double L[N], R[N]; vector <Vector> CH; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); cin >> n >> H; for (int i = 1; i <= n; ++i) { cin >> P[i].x >> P[i].y; } for (int i = 2; i <= n; ++i) { while (CH.size() >= 2 && CCW (*----CH.end(), CH.back(), P[i]) >= 0) { CH.pop_back(); } CH.push_back (P[i]); if (i % 2 == 1) { L[i] = getintersect (CH.back(), *----CH.end()); } } CH.clear(); for (int i = n - 1; i >= 1; --i) { while (CH.size() >= 2 && CCW (*----CH.end(), CH.back(), P[i]) <= 0) { CH.pop_back(); } CH.push_back(P[i]); if (i % 2 == 1) { R[i] = getintersect (CH.back(), *----CH.end()); } } int ans = 0; vector <pair <long double, long double>> range; for (int i = 3; i <= n - 2; i += 2) { range.push_back ({L[i], R[i]}); } sort (range.begin(), range.end()); for (int i = 0; i < range.size();) { int j = i; long double to = 1e9; while (j < range.size() && range[j].first <= to) { to = min(to, range[j].second), ++j; } ++ans; i = j; } cout << ans; }