#include <cstdlib>
#include <cstdio>

using namespace std;

typedef struct
{
    int x;
    int y;
}punct;

int compare(const void *a , const void *b)
{
    punct p1 = *(punct*)a;
    punct p2 = *(punct*)b;
    if (p1.x != p2.x)
    {
        return p1.x - p2.x;
    }
    else
    {
        return p2.y - p1.y;
    }
}

int main()
{
    FILE *input = fopen("text.txt","r");
    int N;
    fscanf(input,"%d",&N);
    punct *a = (punct*)malloc(N * sizeof(punct));


    for (int i =0;i<N;i++)
    {

        fscanf(input,"%d%d",&a[i].x,&a[i].y);
    }

    qsort(a,N,sizeof(punct),compare);

    for (int i = 0;i<N;i++)
    {
        printf("%d%d\n",a[i].x,a[i].y);
    }

    return 0;
}