#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <string>
#include <set>
#include <map>
#include <vector>
#include <queue>
#define ll long long
#define db double
using namespace std;
const ll N = 2e5 + 100; 
ll tt;
char h[N],s[N];
void solve() {
	scanf("%s",h + 1);
	scanf("%s",s + 1);
	ll n = strlen(h + 1);
	ll m = strlen(s + 1);
	if ((h[n] & 1) ^ (s[m] & 1)) {
		printf("Impossible\n");
	} else {
		printf("Possible\n");
	}
}
int main() {
	tt = 1;
	while(tt) {
		solve();
		tt--;
	}
	return 0;
}