#include<iostream>

using namespace std;
const int N=510;
int p[N][N];
int n;
int main(){
    cin>>n;
    for(int i=0;i<n;i++)
        for(int j=0;j<n;j++)
            cin>>p[i][j];
    int x=0,y=0;
    cout<<p[x][y]<<" ";
    while(x!=n-1||y!=n-1){
        if(y+1<n) {
            cout<<p[x][++y]<<" ";
            if(x+1<n&&y-1>=0)
                while(x+1<n&&y-1>=0) cout<<p[++x][--y]<<" ";
            else if(y+1<n&&x-1>=0)
                while(y+1<n&&x-1>=0) cout<<p[--x][++y]<<" ";
        }
        if(x+1<n){ 
            cout<<p[++x][y]<<" ";
            if(x+1<n&&y-1>=0)
                while(x+1<n&&y-1>=0) cout<<p[++x][--y]<<" ";
            else if(y+1<n&&x-1>=0)
                while(y+1<n&&x-1>=0) cout<<p[--x][++y]<<" ";
        }
    }
    return 0;
}