#include<stdio.h>

#include<math.h>

int main()

{

int k,j,m;

printf("please input a positive number\n");

scanf("%d",&m);

/*printf("------------------------\n");

for(k=1;k<=2*m+1;k++)

{

for(j=1;j<=abs(m+1-k);j++)

printf(" ");

for(j=1;j<=-2*abs(k-m-1)+2*m+1;j++)

printf("*");

putchar('\n');

}

printf("--------------------------\n");

for(k=-m;k<=m;k++)

{

for(j=-m;j<=m;j++)

if(abs(k)+abs(j)<=m)

printf("*");

else

printf(" ");

putchar('\n');

}

printf("--------------------------\n");*/

for(j=1;j<=2*m+1;j++)

{

for(k=1;k<=2*m+1;k++)

{ if(j<=m+1)

if(((j+k)>=m+2)&&((j+k)<=m+2+2*(k-1)))

printf("*");

else

printf(" ");

else

if(((j+k)>=m+2+2*(k-m-1))&&((j+k)<=2*m+2))

printf("*");

else

printf(" ");

}

putchar('\n');

}

}