// editor2
#include<stdio.h>
int main(){
    int m,n;
    scanf("%d %d", &m, &n);
    if(m<=0 || n<=0){
        printf("-1");
        return 0;
    }
    int matrix[m][n];
    for(int i=0; i<m; i++){
        for(int j=0; j<n; j++){
            scanf("%d", &matrix[i][j]);
        }
    }
    int top =0, bottom =m -1;
    int left=0, right =n-1;
    while(top<=bottom && left<=right){
        for(int i =left; 1<=right;i++)
        printf("%d", matrix[top][i]);
        top++;
        for(int i=top;i<=bottom;i++)
        printf("%d", matrix[i][right]);
        right--;
        if(top<=bottom){
            for(int i=right;i>=left;i--)
            printf("%d", matrix[bottom][i]);
        bottom--;
    }
    if(left <= right){
        for(int i= bottom; i>= top; i--){
        printf("%d ", matrix[i][left]);
        left++;
        }
    re
    }
}