#include <cmath>#include <cstdio>struct Point{ int x, y, z; Point() { } Point(int x, int y, int z) : x(x), y(y), z(z) { }};int sign(int x){ if (x > 0) return 1; else if (x < 0) return -1; else return 0;}double sqr(int x){ return x * x;}double abs(const Point& p){ return sqrt(sqr(p.x) + sqr(p.y) + sqr(p.z));}Point operator-(const Point& a, const Point& b){ return Point(a.x - b.x, a.y - b.y, a.z - b.z);}int dmult(const Point& a, const Point& b){ return a.x * b.x + a.y * b.y + a.z * b.z;}Point xmult(const Point& a, const Point& b){ return Point(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);}Point p[32];int s[32], ss;int main(){ int n; bool flag; double ans; while (scanf("%d", &n) != EOF && n > 0) { for (int i = 0; i < n; i++) { scanf("%d%d%d", &p[i].x, &p[i].y, &p[i].z); } ans = 0; for (int i = 0; i < n; i++) { for (int j = i + 1; j < n; j++) { for (int k = j + 1; k < n; k++) { Point dn = xmult(p[j] - p[i], p[k] - p[i]); ss = 0; flag = true; for (int t = 0; t < n; t++) { s[t] = sign(dmult(dn, p[t] - p[i])); if (s[t] != 0) { if (ss == 0) { ss = s[t]; } else if (ss != s[t]) { flag = false; break; } } } if (flag) { ans += abs(dn); } } } } printf("%.0lfn", ans / 2); } return 0;}
