#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define X first #define Y second #define pb push_back #define rep(X,Y) for (int (X) = 0;(X) < (Y);++(X)) #define rrep(X,Y) for (int (X) = (Y)-1;(X) >=0;--(X)) #define repe(X,Y) for ((X) = 0;(X) < (Y);++(X)) #define peat(X,Y) for (;(X) < (Y);++(X)) #define all(X) (X).begin(),(X).end() #define rall(X) (X).rbegin(),(X).rend() #define eb emplace_back #define UNIQUE(X) (X).erase(unique(all(X)),(X).end()) using namespace std; typedef long long ll; typedef pair pii; typedef pair pll; template using vv=vector>; template ostream& operator<<(ostream &os, const vector &t) { os<<"{"; rep(i,t.size()) {os< ostream& operator<<(ostream &os, const pair &t) { return os<<"("<>p>>q; ll g=p+q; if(p && q){ if(p!=q)g=__gcd(g,abs(p-q)); g=__gcd(g,2*__gcd(p,q)); } if(!g){ cout<<0<>n; ll x,y,re=n; rep(i,n){ cin>>x>>y; int f=0; for(ll d:{0ll,p,q}){ ll xx=abs(x-d),yy=abs(y-d); if(xx%g==0 && yy%g==0) f=1; } if(!f) --re; } cout<