Плетка

#include <cstdio>

int main()
{
    int i,j,n;
    scanf("%d",&n);
    for (i = 0; i < n; ++i)
    {
        for (j = 0 ; j < n ; ++j)
        {
            if(j == 0 || j == n-1)
                printf("%%");
            else if(i == 0 || i == n-1)
                printf("@");
            else
                printf(".");
        }
        printf("\n");
    }
    return 0;
}