#include <iostream>
#include <cmath>
using namespace std;

struct point
{
    float x, y, z;
};
double dlina(point a)
{
    return sqrt(a.x*a.x + a.y*a.y + a.z*a.z);
}
void main()
{
    point a[100];
    int n;
    cout << "Vvedite n";
    cin >> n;
    for (int i = 0; i<n; i++)
    {
        cout << "Vvedite koordinatu" << i << "ot tochki";
        cin >> a[i].x >> a[i].y >> a[i].z;
    }
    double max = 0; int k = 0;
    for (int i = 0; i<n; i++)
        if (dlina(a[i])>max)
        {
            max = dlina(a[i]);
            k = i;
        }
    cout << "k=" << k;
}