#include <bits/stdc++.h>
using namespace std;
int N,H;
pair<int,int> A[1000005];
vector< pair<long double,long double> > lst;
int main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> N >> H;
for (int i = 0; i < N; ++i) cin >> A[i].first >> A[i].second;
for (int i = 2; i < N-1; i += 2) {
long double x1 = A[i].first - (long double) (A[i].first - A[i-1].first) / (A[i-1].second - A[i].second) * (H - A[i].second);
long double x2 = A[i].first + (long double) (A[i+1].first - A[i].first) / (A[i+1].second - A[i].second) * (H - A[i].second);
lst.emplace_back(x2,x1);
}
sort(lst.begin(),lst.end());
int ans = 0;
long double n = -1e18;
for (auto x: lst) if (n < x.second) ans++, n = x.first;
cout << ans;
return 0;
}
