#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

double f(double x, double y) {
	if (y < x) y += M_PI * 2;
	return y - x;
}

int main() {
	int n; cin >> n;
	vector<int> x(n), y(n);
	for (int i = 0; i < n; i++)
		cin >> x[i] >> y[i];
	bool pos = true;
	for (int i = 0; i < n; i++)
		if (i == 0 || i == n - 1) {
			bool ok = false;
			for (int j = 0; j < n; j++) {
				if (j == i) continue;
				ll dx = x[j] - x[i], dy = y[j] - y[i];
				bool a = false, b = false;
				for (int k = 0; k < n; k++) {
					if (k == i || k == j) continue;
					if ((x[k] - x[i]) * dy - (y[k] - y[i]) * dx > 0)
						a = true;
					else
						b = true;
				}
				if (!a || !b) ok = true;
			}
			if (!ok) pos = false;
		}
		else {
			vector<d_i> p;
			for (int j = 0; j < n; j++) {
				if (j == i) continue;
				p.push_back(d_i(atan2(y[j] - y[i], x[j] - x[i]), j < i));
			}
			int m = p.size();
			sort(p.begin(), p.end());
			bool ok = false;
			for (int j = 0; j < m; j++)
				if (p[j].second != p[(j + 1) % m].second || p[j].second != p[(j + m - 1) % m].second) {
					vector<bool> a(2), b(2);
					for (int k = 0; k < m; k++) {
						if (k == j) continue;
						if (f(p[j].first, p[k].first) < M_PI) a[p[k].second] = true;
						else b[p[k].second] = true;
					}
					if (!(a[0] && b[0]) && !(a[1] && b[1]) && !(a[0] && a[1]) && !(b[0] && b[1]))
						ok = true;
				}
			if (!ok) pos = false;
		}
		cout << (pos ? "Possible" : "Impossible") << endl;
}