#include <iostream>

 #include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<stack>

 #include<queue>

 #include<iomanip>

 #include<cmath>

 #include<map>

 #include<vector>

 #include<algorithm>

 #define N 500010

 using namespace std;

 int degree[N],bin[N],id = ;

 struct tree

 {

     int flag,id;

     struct tree* next[];

 }*root;

 struct tree* creat()

 {

     struct tree *p=(struct tree*)malloc(sizeof(struct tree));

     p->flag =;

     for(int i = ; i < ; i++)

         p->next[i] = NULL;

     return p;

 }

 int find(int x)

 {

     if(bin[x] != x)

         bin[x] = find(bin[x]);

     return bin[x];

 }

 int hash(char s[])

 {

     struct tree *p = root;

     for(int i = ; s[i]; i++)

     {

         if(p->next[s[i]-'a'] == NULL)

             p->next[s[i]-'a'] = creat();

         p = p->next[s[i]-'a'];

     }

     if(p->flag != )

     {

         p->flag = ;

         p->id = id++;

     }

     return p->id;

 }

 int check()

 {

     int sum = ;

     int x = find();

     for(int i = ; i < id; i++)

         if(find(i) != x)

             return ;

     for(int i = ; i < id; i++)

     {

         if(degree[i]%)

             sum++;

     }

     if(sum ==  || sum == )

         return ;

     return ;

 }

 int main()

 {

     int u,v,x,y;

     char s1[],s2[];

     memset(degree,,sizeof(degree));

     for(int i=; i<=; i++)

     bin[i]=i;

     root=creat();

     while(scanf("%s %s",s1,s2)!=EOF)

     {

         u =hash(s1);  v =hash(s2);

         degree[u]++;   degree[v]++;

         x=find(u);

         y=find(v);

         if(x!=y)

             bin[x]=y;

     }

     if(check()) printf("Possible\n");

     else printf("Impossible\n");

     return ;

 }