/*
#include <stdio.h>
int main()
{
int i,j,n,m,k=1,x=1;
int arr[101][101]= {};
scanf("%d %d",&n,&m);
for (i=n ; i>=1 ; i--)
{
if (x%2==0)
{
for (j=1 ; j<=m ; j++)
{
arr[i][j]=k;
k++;
}
}
else
{
for (j=m ; j>=1 ; j--)
{
arr[i][j]=k;
k++;
}
}
x++;
}
for (i=1 ; i<=n ; i++)
{
for (j=1 ; j<=m ; j++)
{
printf("%d ",arr[i][j]);
}
printf("\n");
}
return 0;
}
*/
/*
#include <stdio.h> ----> 질문 1474
int main()
{
int arr[101][101] = {};
int i,j,n,m,x=1,k=1;
scanf("%d %d", &n, &m);
for(j = m; j >= 1; j--)
{
if(x%2 == 0)
{
for(i = 1; i<=n; i++)
{
arr[i][j] = k;
k++;
}
}
else
{
for(i= n; i>=1; i--)
{
arr[i][j] = k;
k++;
}
}
x++;
for (i=1 ; i<=n ; i++)
{
for (j=1 ; j<=m ; j++)
{
printf("%d ",arr[i][j]);
}
printf("\n");
}
return 0;
}
}
*/
/*
#include <stdio.h>
int main()
{
int arr[21][21] = {};
int n,i,j,k;
scanf("%d",&n);
for(i = 0; i<n; i++)
{
scanf("%d",&arr[i][0]);
}
for(j = 0; j <n; j++)
{
for(k = 0; k <n; k++)
{
if(k <= j)
{
arr[j+1][k+1] = arr[j+1][k]-arr[j][k];
}
}
}
for(int i = 0; i<n; i++)
{
for(int j = 0; j<n; j++)
{
if(arr[i][j] != 0 )
{
printf("%d ",arr[i][j]);
}
}
printf("\n");
}
return 0;
}
*/
/*
#include <stdio.h> ---->4592 질문
int main()
{
int wpaper[100][100] = {};
int i,j,n, left, under;
int cnt = 0;
scanf("%d", &n);
for (i = 0; i < n; i++)
{
scanf("%d %d", &left, &under);
}
}
*/
/*
#include <stdio.h> --->1510 질문
int main()
{
int arr [50][50]={};
int n,k,i,j;
scanf("%d",&n);
for (i=0 ; i<n*n ; i++)
{
arr[i][j]=k;
k++;
}
}
*/
/*
#include <stdio.h> --->1512 질문
int main()
{
int arr[101][101]={};
int n,x,y,i,j;
scanf("%d\n%d %d",&n,&x,&y);
arr[x][y]=1;
int k=arr[x][y];
for (i=1; i<=x ; i++)
{
arr[x][y]=k;
k++;
}
}
*/