#include using namespace std; bool online(int x1, int y1, int x2, int y2, int X, int Y) { return (x2 - x1) * (Y - y1) == (y2 - y1) * (X - x1); } int main() { int N; cin >> N; vector X(N), Y(N); for(int i=0; i> X[i] >> Y[i]; int res = 0; for(int i=0; i