#include <bits/stdc++.h>   int a[40][40], b[40][40], ta[40][40];   int ansx[1010000], ansy[1010000];   int za[1010], zb[1010];   int aaa[40][40], bbb[40][40], aaaa[40][40], bbbb[40][40];   int c[40][40];   int main(void) {     int n, m, i, j, j1, j2, nm, j3, j4;     int ans;     int temp;     int z;     int x, y;     int aa, bb;     int nn, mm;     while (scanf( %d %d , &n, &m) != EOF) {       for (i = 1; i <= 900; i++) {         za[i] = 0;         zb[i] = 0;       }       for (j1 = 1; j1 <= n; j1++) {         for (j2 = 1; j2 <= m; j2++) {           scanf( %d , &a[j1][j2]);           aaaa[j1][j2] = aaa[j1][j2] = a[j1][j2];           za[a[j1][j2]]++;         }       }       for (j1 = 1; j1 <= n; j1++) {         for (j2 = 1; j2 <= m; j2++) {           scanf( %d , &b[j1][j2]);           bbbb[j1][j2] = bbb[j1][j2] = b[j1][j2];           zb[b[j1][j2]]++;         }       }       nm = 0;       if (n == 1 && m == 1) {         ans = -1;       } else if (n == 1 || m == 1) {         if (m == 1) {           for (i = 2; i <= n; i++) {             a[1][i] = a[i][1];             b[1][i] = b[i][1];           }           m = n;           nm = 1;         }         ans = -1;         for (j1 = 1; j1 <= m; j1++) {           for (j2 = 1; j2 < j1; j2++) {             for (i = 1; i <= m; i++) {               ta[1][i] = a[1][i];             }             for (i = j1; i > j2; i--) {               temp = ta[1][i];               ta[1][i] = ta[1][i - 1];               ta[1][i - 1] = temp;             }             z = 1;             for (i = 1; i <= m; i++) {               if (b[1][i] != ta[1][i]) {                 z = 0;                 break;               }             }             if (z) {               ans = 0;               ansx[0] = 1;               ansy[0] = j1;               for (i = j1 - 1; i >= j2; i--) {                 ++ans;                 ansx[ans] = 1;                 ansy[ans] = i;               }               break;             }           }           if (ans < 0) {             for (j2 = j1 + 1; j2 <= m; j2++) {               for (i = 1; i <= m; i++) {                 ta[1][i] = a[1][i];               }               for (i = j1; i < j2; i++) {                 temp = ta[1][i];                 ta[1][i] = ta[1][i + 1];                 ta[1][i + 1] = temp;               }               z = 1;               for (i = 1; i <= m; i++) {                 if (b[1][i] != ta[1][i]) {                   z = 0;                   break;                 }               }               if (z) {                 ans = 0;                 ansx[0] = 1;                 ansy[0] = j1;                 for (i = j1 + 1; i <= j2; i++) {                   ++ans;                   ansx[ans] = 1;                   ansy[ans] = i;                 }                 break;               }             }           }           if (ans > 0) {             break;           }         }       } else {         z = 1;         for (i = 1; i <= 900; i++) {           if (za[i] != zb[i]) {             z = 0;             break;           }         }         ans = -1;         if (z) {           z = 0;           bb = b[n][m];           for (j1 = 1; j1 <= n; j1++) {             for (j2 = 1; j2 <= m; j2++) {               if (bb == a[j1][j2]) {                 z = 1;                 break;               }             }             if (z) {               break;             }           }           ans = 0;           ansx[0] = j1;           ansy[0] = j2;           for (i = j2 - 1; i; i--) {             temp = a[j1][i];             a[j1][i] = a[j1][i + 1];             a[j1][i + 1] = temp;             ++ans;             ansx[ans] = j1;             ansy[ans] = i;           }           for (i = j1 - 1; i; i--) {             temp = a[i][1];             a[i][1] = a[i + 1][1];             a[i + 1][1] = temp;             ++ans;             ansx[ans] = i;             ansy[ans] = 1;           }           nn = n - 2;           for (j1 = 1; j1 <= nn; j1++) {             for (j2 = 1; j2 < m; j2++) {               z = 0;               bb = b[j1][j2];               for (j3 = j1; j3 <= n; j3++) {                 if (j3 == j1) {                   j4 = j2 + 1;                 } else {                   j4 = 1;                 }                 for (; j4 <= m; j4++) {                   if (bb == a[j3][j4]) {                     z = 1;                     break;                   }                 }                 if (z) {                   break;                 }               }               if (!z)                 while (1)                   ;               if (j3 == j1) {                 c[j1][j2] = 1;                 for (i = j2 + 1; i <= j4; i++) {                   temp = a[j1][i];                   a[j1][i] = a[j1][i - 1];                   a[j1][i - 1] = temp;                   ++ans;                   ansx[ans] = j1;                   ansy[ans] = i;                 }               } else if (j4 == m) {                 c[j1][j2] = 2;                 for (i = j2 + 1; i <= m; i++) {                   temp = a[j1][i];                   a[j1][i] = a[j1][i - 1];                   a[j1][i - 1] = temp;                   ++ans;                   ansx[ans] = j1;                   ansy[ans] = i;                 }                 for (i = j1 + 1; i <= j3; i++) {                   temp = a[i][m];                   a[i][m] = a[i - 1][m];                   a[i - 1][m] = temp;                   ++ans;                   ansx[ans] = i;                   ansy[ans] = m;                 }               } else {                 c[j1][j2] = 3;                 for (i = j2 + 1; i <= m; i++) {                   temp = a[j1][i];                   a[j1][i] = a[j1][i - 1];                   a[j1][i - 1] = temp;                   ++ans;                   ansx[ans] = j1;                   ansy[ans] = i;                 }                 for (i = j1 + 1; i <= j3; i++) {                   temp = a[i][m];                   a[i][m] = a[i - 1][m];                   a[i - 1][m] = temp;                   ++ans;                   ansx[ans] = i;                   ansy[ans] = m;                 }                 for (i = m - 1; i >= j4; i--) {                   temp = a[j3][i];                   a[j3][i] = a[j3][i + 1];                   a[j3][i + 1] = temp;                   ++ans;                   ansx[ans] = j3;                   ansy[ans] = i;                 }                 if (j3 == n) {                   for (i = j4 + 1; i < m; i++) {                     temp = a[j3][i - 1];                     a[j3][i - 1] = a[j3 - 1][i];                     a[j3 - 1][i] = temp;                     temp = a[j3][i + 1];                     a[j3][i + 1] = a[j3 - 1][i];                     a[j3 - 1][i] = temp;                     temp = a[j3][i + 1];                     a[j3][i + 1] = a[j3][i];                     a[j3][i] = temp;                     ++ans;                     ansx[ans] = j3 - 1;                     ansy[ans] = i;                     ++ans;                     ansx[ans] = j3;                     ansy[ans] = i + 1;                     ++ans;                     ansx[ans] = j3;                     ansy[ans] = i;                   }                 } else {                   for (i = j4 + 1; i < m; i++) {                     temp = a[j3][i - 1];                     a[j3][i - 1] = a[j3 + 1][i];                     a[j3 + 1][i] = temp;                     temp = a[j3][i + 1];                     a[j3][i + 1] = a[j3 + 1][i];                     a[j3 + 1][i] = temp;                     temp = a[j3][i + 1];                     a[j3][i + 1] = a[j3][i];                     a[j3][i] = temp;                     ++ans;                     ansx[ans] = j3 + 1;                     ansy[ans] = i;                     ++ans;                     ansx[ans] = j3;                     ansy[ans] = i + 1;                     ++ans;                     ansx[ans] = j3;                     ansy[ans] = i;                   }                 }                 temp = a[j3][m - 1];                 a[j3][m - 1] = a[j3 - 1][m];                 a[j3 - 1][m] = temp;                 ++ans;                 ansx[ans] = j3 - 1;                 ansy[ans] = m;                 temp = a[j3][m];                 a[j3][m] = a[j3 - 1][m];                 a[j3 - 1][m] = temp;                 ++ans;                 ansx[ans] = j3;                 ansy[ans] = m;               }               if (j3 != j1) {                 for (i = j3 - 1; i > j1; i--) {                   temp = a[i + 1][m];                   a[i + 1][m] = a[i][m - 1];                   a[i][m - 1] = temp;                   temp = a[i - 1][m];                   a[i - 1][m] = a[i][m - 1];                   a[i][m - 1] = temp;                   temp = a[i - 1][m];                   a[i - 1][m] = a[i][m];                   a[i][m] = temp;                   ++ans;                   ansx[ans] = i;                   ansy[ans] = m - 1;                   ++ans;                   ansx[ans] = i - 1;                   ansy[ans] = m;                   ++ans;                   ansx[ans] = i;                   ansy[ans] = m;                 }                 temp = a[j1][m - 1];                 a[j1][m - 1] = a[j1 + 1][m];                 a[j1 + 1][m] = temp;                 ++ans;                 ansx[ans] = j1;                 ansy[ans] = m - 1;                 temp = a[j1][m - 1];                 a[j1][m - 1] = a[j1][m];                 a[j1][m] = temp;                 ++ans;                 ansx[ans] = j1;                 ansy[ans] = m;                 j4 = m;               }               for (i = j4 - 1; i > j2; i--) {                 temp = a[j1][i + 1];                 a[j1][i + 1] = a[j1 + 1][i];                 a[j1 + 1][i] = temp;                 temp = a[j1][i - 1];                 a[j1][i - 1] = a[j1 + 1][i];                 a[j1 + 1][i] = temp;                 temp = a[j1][i - 1];                 a[j1][i - 1] = a[j1][i];                 a[j1][i] = temp;                 ++ans;                 ansx[ans] = j1 + 1;                 ansy[ans] = i;                 ++ans;                 ansx[ans] = j1;                 ansy[ans] = i - 1;                 ++ans;                 ansx[ans] = j1;                 ansy[ans] = i;               }               if (a[j1][j2] != b[j1][j2]) {                 printf( %d %d , j1, j2);                 for (j3 = 1; j3 <= j1; j3++) {                   for (j4 = 1; j4 <= m; j4++) {                     printf( %d  , c[j3][j4]);                   }                   printf(  n );                 }                 return 0;               }             }             z = 0;             bb = b[j1][j2];             for (j3 = j1 + 1; j3 <= n; j3++) {               for (j4 = 1; j4 <= m; j4++) {                 if (bb == a[j3][j4]) {                   z = 1;                   break;                 }               }               if (z) {                 break;               }             }             if (j4 == m) {               for (i = j1 + 1; i <= j3; i++) {                 temp = a[i][m];                 a[i][m] = a[i - 1][m];                 a[i - 1][m] = temp;                 ++ans;                 ansx[ans] = i;                 ansy[ans] = m;               }             } else {               for (i = j1 + 1; i <= j3; i++) {                 temp = a[i][m];                 a[i][m] = a[i - 1][m];                 a[i - 1][m] = temp;                 ++ans;                 ansx[ans] = i;                 ansy[ans] = m;               }               for (i = m - 1; i >= j4; i--) {                 temp = a[j3][i];                 a[j3][i] = a[j3][i + 1];                 a[j3][i + 1] = temp;                 ++ans;                 ansx[ans] = j3;                 ansy[ans] = i;               }               if (j3 == n) {                 for (i = j4 + 1; i < m; i++) {                   temp = a[j3][i - 1];                   a[j3][i - 1] = a[j3 - 1][i];                   a[j3 - 1][i] = temp;                   temp = a[j3][i + 1];                   a[j3][i + 1] = a[j3 - 1][i];                   a[j3 - 1][i] = temp;                   temp = a[j3][i + 1];                   a[j3][i + 1] = a[j3][i];                   a[j3][i] = temp;                   ++ans;                   ansx[ans] = j3 - 1;                   ansy[ans] = i;                   ++ans;                   ansx[ans] = j3;                   ansy[ans] = i + 1;                   ++ans;                   ansx[ans] = j3;                   ansy[ans] = i;                 }               } else {                 for (i = j4 + 1; i < m; i++) {                   temp = a[j3][i - 1];                   a[j3][i - 1] = a[j3 + 1][i];                   a[j3 + 1][i] = temp;                   temp = a[j3][i + 1];                   a[j3][i + 1] = a[j3 + 1][i];                   a[j3 + 1][i] = temp;                   temp = a[j3][i + 1];                   a[j3][i + 1] = a[j3][i];                   a[j3][i] = temp;                   ++ans;                   ansx[ans] = j3 + 1;                   ansy[ans] = i;                   ++ans;                   ansx[ans] = j3;                   ansy[ans] = i + 1;                   ++ans;                   ansx[ans] = j3;                   ansy[ans] = i;                 }               }               temp = a[j3][m - 1];               a[j3][m - 1] = a[j3 - 1][m];               a[j3 - 1][m] = temp;               ++ans;               ansx[ans] = j3 - 1;               ansy[ans] = m;               temp = a[j3][m];               a[j3][m] = a[j3 - 1][m];               a[j3 - 1][m] = temp;               ++ans;               ansx[ans] = j3;               ansy[ans] = m;             }             for (i = j3 - 1; i > j1; i--) {               temp = a[i + 1][m];               a[i + 1][m] = a[i][m - 1];               a[i][m - 1] = temp;               temp = a[i - 1][m];               a[i - 1][m] = a[i][m - 1];               a[i][m - 1] = temp;               temp = a[i - 1][m];               a[i - 1][m] = a[i][m];               a[i][m] = temp;               ++ans;               ansx[ans] = i;               ansy[ans] = m - 1;               ++ans;               ansx[ans] = i - 1;               ansy[ans] = m;               ++ans;               ansx[ans] = i;               ansy[ans] = m;             }             for (i = m - 1; i; i--) {               temp = a[j1 + 1][i];               a[j1 + 1][i] = a[j1 + 1][i + 1];               a[j1 + 1][i + 1] = temp;               ++ans;               ansx[ans] = j1 + 1;               ansy[ans] = i;             }             if (a[j1][j2] != b[j1][j2]) {               printf( %d %d , j1, j2);               return 0;             }           }           nn = n - 1;           j3 = ansx[0];           j4 = ansy[0];           for (i = 1; i <= ans; i++) {             x = ansx[i];             y = ansy[i];             temp = aaaa[x][y];             aaaa[x][y] = aaaa[j3][j4];             aaaa[j3][j4] = temp;             j3 = x;             j4 = y;           }           z = 0;           for (j1 = 1; j1 < nn; j1++) {             for (j2 = 1; j2 <= m; j2++) {               if (aaaa[j1][j2] != bbbb[j1][j2]) {                 z = 1;                 break;               }             }             if (z) {               break;             }           }           if (z) {             while (1)               ;           }           mm = m - 2;           for (j2 = 1; j2 <= mm; j2++) {             bb = b[nn][j2];             if (bb == a[n][j2]) {               temp = a[n][j2];               a[n][j2] = a[nn][j2];               a[nn][j2] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = j2;             } else {               for (j4 = j2 + 1; j4 <= m; j4++) {                 if (bb == a[nn][j4]) {                   j3 = nn;                   break;                 }                 if (bb == a[n][j4]) {                   j3 = n;                   break;                 }               }               if (j3 == nn) {                 for (i = j2 + 1; i <= j4; i++) {                   temp = a[nn][i];                   a[nn][i] = a[nn][i - 1];                   a[nn][i - 1] = temp;                   ans++;                   ansx[ans] = nn;                   ansy[ans] = i;                 }               } else {                 for (i = j2 + 1; i < j4; i++) {                   temp = a[nn][i];                   a[nn][i] = a[nn][i - 1];                   a[nn][i - 1] = temp;                   ans++;                   ansx[ans] = nn;                   ansy[ans] = i;                 }                 temp = a[n][j4];                 a[n][j4] = a[nn][j4 - 1];                 a[nn][j4 - 1] = temp;                 ans++;                 ansx[ans] = n;                 ansy[ans] = j4;                 temp = a[n][j4];                 a[n][j4] = a[nn][j4];                 a[nn][j4] = temp;                 ans++;                 ansx[ans] = nn;                 ansy[ans] = j4;               }               for (j4--; j4 > j2; j4--) {                 temp = a[n][j4];                 a[n][j4] = a[nn][j4 + 1];                 a[nn][j4 + 1] = temp;                 ans++;                 ansx[ans] = n;                 ansy[ans] = j4;                 temp = a[n][j4];                 a[n][j4] = a[nn][j4 - 1];                 a[nn][j4 - 1] = temp;                 ans++;                 ansx[ans] = nn;                 ansy[ans] = j4 - 1;                 temp = a[nn][j4];                 a[nn][j4] = a[nn][j4 - 1];                 a[nn][j4 - 1] = temp;                 ans++;                 ansx[ans] = nn;                 ansy[ans] = j4;               }               temp = a[n][j2];               a[n][j2] = a[nn][j2 + 1];               a[nn][j2 + 1] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = j2;             }             bb = b[n][j2];             for (j4 = j2 + 1; j4 <= m; j4++) {               if (bb == a[n][j4]) {                 j3 = n;                 break;               }               if (bb == a[nn][j4]) {                 j3 = nn;                 break;               }             }             if (j3 == n) {               for (i = j2 + 1; i <= j4; i++) {                 temp = a[n][i];                 a[n][i] = a[n][i - 1];                 a[n][i - 1] = temp;                 ans++;                 ansx[ans] = n;                 ansy[ans] = i;               }             } else {               for (i = j2 + 1; i < j4; i++) {                 temp = a[n][i];                 a[n][i] = a[n][i - 1];                 a[n][i - 1] = temp;                 ans++;                 ansx[ans] = n;                 ansy[ans] = i;               }               temp = a[nn][j4];               a[nn][j4] = a[n][j4 - 1];               a[n][j4 - 1] = temp;               ans++;               ansx[ans] = nn;               ansy[ans] = j4;               temp = a[n][j4];               a[n][j4] = a[nn][j4];               a[nn][j4] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = j4;             }             for (j4--; j4 > j2; j4--) {               temp = a[nn][j4];               a[nn][j4] = a[n][j4 + 1];               a[n][j4 + 1] = temp;               ans++;               ansx[ans] = nn;               ansy[ans] = j4;               temp = a[nn][j4];               a[nn][j4] = a[n][j4 - 1];               a[n][j4 - 1] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = j4 - 1;               temp = a[n][j4];               a[n][j4] = a[n][j4 - 1];               a[n][j4 - 1] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = j4;             }             temp = a[nn][j2 + 1];             a[nn][j2 + 1] = a[n][j2 + 1];             a[n][j2 + 1] = temp;             ans++;             ansx[ans] = nn;             ansy[ans] = j2 + 1;           }           mm = m - 1;           if (b[nn][mm] == a[nn][m]) {             j1 = nn;             j2 = m;           } else if (b[nn][mm] == a[n][mm]) {             j1 = n;             j2 = mm;           } else {             j1 = n;             j2 = m;           }           temp = a[nn][mm];           a[nn][mm] = a[j1][j2];           a[j1][j2] = temp;           ans++;           ansx[ans] = j1;           ansy[ans] = j2;           z = 0;           if (a[n][m] != b[n][m]) {             z = 1;           } else if (a[nn][m] != b[nn][m]) {             z = 1;           } else if (a[n][mm] != b[n][mm]) {             z = 1;           }           while (z) {             if (j1 == n && j2 == m) {               temp = a[n][m];               a[n][m] = a[n][mm];               a[n][mm] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = mm;               j1 = n;               j2 = mm;             } else if (j1 == n) {               temp = a[n][mm];               a[n][mm] = a[nn][m];               a[nn][m] = temp;               ans++;               ansx[ans] = nn;               ansy[ans] = m;               j1 = nn;               j2 = m;             } else {               temp = a[nn][m];               a[nn][m] = a[n][m];               a[n][m] = temp;               ans++;               ansx[ans] = n;               ansy[ans] = m;               j1 = n;               j2 = m;             }             z = 0;             if (a[n][m] != b[n][m]) {               z = 1;             } else if (a[nn][m] != b[nn][m]) {               z = 1;             } else if (a[n][mm] != b[n][mm]) {               z = 1;             }           }         }       }       if (ans != -1) {         if (nm) {           j4 = ansx[0];           j3 = ansy[0];         } else {           j3 = ansx[0];           j4 = ansy[0];         }         for (i = 1; i <= ans; i++) {           if (nm) {             y = ansx[i];             x = ansy[i];           } else {             x = ansx[i];             y = ansy[i];           }           temp = aaa[x][y];           aaa[x][y] = aaa[j3][j4];           aaa[j3][j4] = temp;           j3 = x;           j4 = y;         }         z = 0;         for (j1 = 1; j1 <= n; j1++) {           for (j2 = 1; j2 <= m; j2++) {             if (aaa[j1][j2] != bbb[j1][j2]) {               z = 1;               break;             }           }           if (z) {             break;           }         }         if (z) {           printf( %d n , 5 / 0);         }       }       printf( %d n , ans);       if (ans > 1000000)         while (1)           ;       if (nm) {         for (i = 0; i <= ans; i++) {           printf( %d %d n , ansy[i], ansx[i]);         }       } else {         for (i = 0; i <= ans; i++) {           printf( %d %d n , ansx[i], ansy[i]);         }       }       printf(  n );     }     return 0;   }