#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>
#include <string>
#include <set>
#include <cstdio>
#include <iomanip>
#include <map>
#include <stdio.h>
#include <math.h>
#include <queue>
#include <random>
#define and &&
#define or ||
using namespace std;
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)

#define PI acos(-1.0)
using namespace std;
const long long inf = 1e10;
const long long m = 1e9 + 7;
const long double e = 0.0000001;

int gcd(int a, int b) { return b ? a : gcd(b, a % b); }

int toNum(char s) {
	return s - 'a';
}


double S(int x1, int y1, int x2, int y2) {
	return abs(x1 * y2 - y1 * x2) / 2.0;
}

int f(double a, double b, double c, double x, double y) {
	double k = a * x + b * y + c;
	if (k > 0)
		return 1;
	else if (k < 0)
		return -1;
	else if (k == 0)
		return 0;
}

bool isCrossing(double x1, double y1, double x2, double y2, double x11, double y11, double x22, double y22)
{
	double a1 = y2 - y1;
	double b1 = -(x2 - x1);
	double c1 = -x1 * (y2 - y1) + y1 * (x2 - x1);
	double a2 = y22 - y11;
	double b2 = -(x22 - x11);
	double c2 = -x11 * (y22 - y11) + y11 * (x22 - x11);
	double pos1 = f(a1, b1, c1, x11, y11);
	double pos2 = f(a1, b1, c1, x22, y22);
	double pos3 = f(a2, b2, c2, x1, y1);
	double pos4 = f(a2, b2, c2, x2, y2);
	if (!((x1 == x2 and y1 == y2) or (x11 == x22 and y11 == y22))) {
		if (!(c2 * a1 == a2 * c1 and b1 * a2 == b2 * a1 and c1 * b2 == c2 * b1)) {
			if (pos1 != pos2 and pos3 != pos4) {
				return true;
			}
			else {
				return false;
			}
		}
		else {
			if (x1 == x2 and x2 == x11 and x11 == x22) {
				if ((min(y1, y2) <= y11 and y11 <= max(y1, y2)) or (min(y1, y2) <= x22 and y22 <= max(y1, y2))) {
					return true;
				}
				else {
					return false;
				}
			}
			else if ((min(x1, x2) <= x11 and x11 <= max(x1, x2)) or (min(x1, x2) <= x22 and x22 <= max(x1, x2))) {
				return true;
			}
			else {
				return false;
			}
		}
	}
	else {
		if (x1 == x2 and y1 == y2) {
			if (f(a2, b2, c2, x1, y1) == 0) {
				return true;
			}
			else {
				return false;
			}
		}
		else if (x11 == x22 and y11 == y22) {
			if (f(a1, b1, c1, x11, y11) == 0) {
				return true;
			}
			else {
				return false;
			}

		}
	}
}



double len(vector<double>gg) {
	return pow((gg[0] * gg[0] + gg[1] * gg[1]), 0.5);
}

bool isRight(vector<double>first, vector<double>second) {
	double ans = first[0] * second[0] + first[1] * second[1];
	if (abs(ans) < e)
		return true;
	else
		return false;
}


double ax, bx, cx, dx, ay, by, cy, dy;
vector <double> ab(2);
vector <double> ac(2);
vector <double> dc(2);
vector <double> db(2);

void input() {
	cin >> ax >> ay;
	cin >> bx >> by;
	cin >> dx >> dy;
	cin >> cx >> cy;
	ab[0] = bx - ax;
	ab[1] = by - ay;
	ac[0] = cx - ax;
	ac[1] = cy - ay;
	dc[0] = cx - dx;
	dc[1] = cy - dy;
	db[0] = bx - dx;
	db[1] = by - dy;
}

void solve() {
	if ((isCrossing(ax, ay, bx, by, cx, cy, dx, dy) || isCrossing(ax, ay, cx, cy, bx, by, dx, dy)))
		cout << "self-intersecting polyline";
	else if (!(isCrossing(ax, ay, dx, dy, bx, by, cx, cy)))
		cout << "non-convex polygon";
	else if (abs(len(ab) - len(dc)) < e && abs(len(ab) - len(db)) < e && abs(len(ac) - len(dc)) < e && isRight(ab, ac) && isRight(dc, db))
		cout << "square";
	else if (abs(len(ab) - len(dc)) < e && abs(len(ab) - len(db)) < e && abs(len(ac) - len(dc)) < e)
		cout << "rhombus";
	else if (isRight(ab, ac) && isRight(dc, db))
		cout << "rectangle" << "\n";
	else if (abs(ab[0] * dc[1] - ab[1] * dc[0]) < e && abs(ac[0] * db[1] - ac[1] * db[0]) < e)
		cout << "parallelogram";
	else if (abs(ab[0] * dc[1] - ab[1] * dc[0]) < e || abs(ac[0] * db[1] - ac[1] * db[0]) < e)
		cout << "trapezoid";
	else
		cout << "convex polygon";
}

int main() {
	IOS;
	input();
	solve();
}