#include <bits/stdc++.h>   using namespace std;   void swap(int ar[], int i, int j) {     int aux = ar[j];     ar[j] = ar[i];     ar[i] = ar[j];   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     int n, m;     cin >> n >> m;     int Ma[n][m];     int Mb[n][m];     for (int i = 0; i < n; i++)       for (int k = 0; k < m; k++) cin >> Ma[i][k];     for (int i = 0; i < n; i++)       for (int k = 0; k < m; k++) {         int aux;         cin >> aux;         if (aux <= Ma[i][k]) {           int aux2 = Ma[i][k];           Ma[i][k] = aux;           Mb[i][k] = aux2;         } else           Mb[i][k] = aux;       }     for (int i = 0; i < n; i++)       for (int k = 1; k < m; k++)         if (Ma[i][k] <= Ma[i][k - 1] || Mb[i][k] <= Mb[i][k - 1]) {           cout <<  Impossible ;           return 0;         }     for (int k = 0; k < m; k++)       for (int i = 1; i < n; i++)         if (Ma[i][k] <= Ma[i - 1][k] || Mb[i][k] <= Mb[i - 1][k]) {           cout <<  Impossible ;           return 0;         }     cout <<  Possible ;     return 0;   }   