#include <bits/stdc++.h>
#define ll long long
#define loop(i, a, b) for(ll i=a;i<b;i++)
#define pool(i, a, b) for(ll i=a-1;i>=b;i--)
#define fore(i, a) for(auto&& i:a)
#define fi first
#define se second
#define ps(a) push_back(a)
#define pb(a) pop_back(a)
#define sc scanf
#define vc vector
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define llmax LLONG_MAX/2
#define llmin -LLONG_MAX/2
using namespace std;
#define mn 500100
#define par pair<ll, ll>
#define ld long double
#define mod 1000000007
ll vecpro(par s, par p1, par p2){
p1.fi-=s.fi;p1.se-=s.se;
p2.fi-=s.fi;p2.se-=s.se;
return p1.fi * p2.se - p2.fi * p1.se;
}
par inter(par p1, par p2, ll h){return make_pair(((h-p1.se) * (p2.fi - p1.fi) + p1.fi * (p2.se - p1.se)) , (p2.se - p1.se)) ;}
vc<par> gt(vc<par> a, ll h ){
ll n=a.size();
vc<par> st;
vc<par> ret;
for(ll i=1;i<n;i+=2){
while(st.size()>=2 and vecpro(st[st.size()-1], st[st.size()-2], a[i-1])<0) st.pop_back();
st.ps(a[i-1]);
while(st.size()>=2 and vecpro(st[st.size()-1], st[st.size()-2], a[i])<0) st.pop_back();
ret.ps(inter(st.back(), a[i], h));
//cout << st.back().fi<<" "<<st.back().se<<" "<<a[i].fi<<" "<<a[i].se <<" "<<inter(st.back(), a[i], h)<<endl;
}
return ret;
}
ll qcmp(par a, par b){return a.fi * b.se < a.se * b.fi;}
ll cmp(pair<par, par> a, pair<par, par> b){
return qcmp(a.fi, b.fi);
}
int main() {
ll n, h;cin >> n>>h;
vc<par> poi;
loop(i, 0, n){
ll x, y;cin >> x >> y;
if(i!=0 and i!=n-1)poi.ps(make_pair(x, y));
}
vc<par> a=gt(poi, h);
fore(v, a) if(v.se<0) v.fi*=-1, v.se*=-1;
reverse(all(poi));
fore(v, poi) v.fi=-v.fi;
vc<par> b=gt(poi, h);
fore(v, b) v.fi=-v.fi;
fore(v, b) if(v.se<0) v.fi*=-1, v.se*=-1;
reverse(all(b));
n=a.size();
vc<pair<par, par>> ints;
loop(i, 0, n) ints.ps(make_pair(a[i], b[i]));
sort(all(ints), cmp);
//loop(i, 0, n) cout << ints[i].fi << " "<< ints[i].se<<endl;
par cur=make_pair(llmax, -1); ll ans=0;
pool(i, n, 0){
if(cur.fi==llmax or qcmp(ints[i].se, cur)) ans++, cur=ints[i].fi;
}
cout << ans<<endl;
}
