#include <iostream>
#include <stdio.h>
using namespace std;
struct point { int x, y; };
double g(struct point a, struct point b, struct point k){
return (k.x - a.x) * (b.y - a.y) - (k.y - a.y) * (b.x - a.x);
} // определяем местоположение точки K относительно прямой АВ
bool f(struct point a, struct point b, struct point c, struct point k){
return g(a, b, c) * g(a, b, k) >= 0;
}
int main() {
struct point a { 1, 4 }, b { 5, -4 }, c { -5, -3 };
int x, y;
struct point k { k.x, k.y };
cin >> k.x >> k.y;
cout << ((f(a,b,c,k) && f(b,c,a,k) && f(c,a,b,k)) ? "yes" : "no");
return 0;
}
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