XDU 1055

#include<stdio.h>
#include<cstring>
int main()
{
    //freopen("orz.txt","w",stdout);
    int i,j,n,m,x,y;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        int c[n][m];
        int d[n*m];
        memset(c,0,sizeof(0));
        for(i=0;i<n;i++){
            for(j=0;j<m;j++)
                scanf("%d",&c[i][j]);   
        }
        d[0]=c[x=0][y=0];
        int vis=1,k=0;
        while(vis<n*m)
        {
            if(x+1<n){
                d[++k]=c[++x][y];
                vis++;
            } 
            else{
                d[++k]=c[x][++y];
                vis++;
            } 
            while(x>0&&y<m-1)
            {
                d[++k]=c[--x][++y];
                vis++;
            }       
            if(y+1<m){
                d[++k]=c[x][++y];
                vis++;
            } 
            else{
                d[++k]=c[++x][y];
                vis++;
            }
            while(y>0&&x<n-1) 
            {
                d[++k]=c[++x][--y];
                vis++;
            }
        }
        for(int i=0;i<n*m-1;i++)
            printf("%d ",d[i]);
        printf("%d\n",d[n*m-1]);
    }
    return 0;
}