#include <atcoder/all>
#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define REP(i, m, n) for(int i = (int)(m); i < (int)(n); i++)
using namespace std;
using namespace atcoder;
using mint = modint998244353;
const int inf = 1000000007;
const ll longinf = 1ll << 60;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    string s, h;
    cin >> s >> h;
    int v = s.back() - h.back();
    cout << (v % 2 == 0 ? "Possible" : "Impossible") << endl;
    return 0;
}