#include <iostream>
#include <cmath>
using namespace std;
int main() {
double ax, ay, az, bx, by, bz, cx, cy, cz, V, V1;
cin >> ax >> ay >> az >> bx >> by >> bz >> cx >> cy >> cz; //Ввод координат векторов.
V = (ax*((by*cz)+(cy*bz)))-ay*((bx*cz)+(cx*bz))+az*((bx*cy)+(cx*by)); //Вычисление объёма.
cout << abs(V); //Выводим модуль значения определителя.
return 0;
}
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