#include<iostream>
#include<algorithm>
#include<string>
#include<vector>
#include<queue>
#include<cmath>
#include<functional>
using namespace std;
int n, m, dp[100][9000];
int main() {
	cin >> n >> m;
	dp[0][5000] = 1;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < 9000; j++) {
			if (dp[i][j] == 0)continue;
			dp[i + 1][j + i + 1] = 1; dp[i + 1][j - i - 1] = 1;
		}
	}
	if (dp[n][5000 + m] == 1)cout << "Possible" << endl;
	else cout << "Impossible" << endl;
	return 0;
}