#include <bits/stdc++.h> 
using namespace std;
using ll =long long;
#define all(v) v.begin(),v.end()
 #define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)

ll INF=2e18;


int main() {
    ios::sync_with_stdio(false);
  cin.tie(0);
  
  string H,S;cin>>H>>S;

  ll a=H.back()-'0';
  ll b=S.back()-'0';


  if(H==S||(a%2==b%2)) {
    cout<<"Possible"<<endl;
  }
  else cout<<"Impossible"<<endl;

}