#include <algorithm>
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
bool dp[51][6000];
int main(){
  int n, m;
  cin >> n >> m;
  if(n==1){
    cout << "Impossible" << endl;
    return 0;
  }
  FOR(i,0,n+1){
    FOR(j,0,6000){
      dp[i][j] = false;
    }
  }
  dp[0][3000] = true;
  FOR(i,0,n){
    FOR(j,0,6000){
      if(!dp[i][j]) continue;
      dp[i+1][j+(i+1)] = true;
      dp[i+1][j-(i+1)] = true;
    }
  }
  cout << (dp[n][m+3000] ? "Possible" : "impossible") << endl;
  return 0;
}