//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;
}
