#include<cstdio>
int n,i,m,v[1000001],k,j,l,r,a[5000001],b[5000001],t;
int main()
{   freopen("interclasari.in","r",stdin),
    freopen("interclasari.out","w",stdout),
    scanf("%d",&n);
    while(n--)
    {   scanf("%d",&m);
		for(j=1;j<=m;j++) scanf("%d",v+j);
          for(t=0,j=l=1;j<=k&&l<=m;)
			  if(a[j]>v[l]) b[++t]=v[l++]; else b[++t]=a[j++];
          for(;j<=k;b[++t]=a[j++]);
          for(;l<=m;b[++t]=v[l++]);
          for(k+=m,j=1;j<=k;j++) a[j]=b[j];
    }
    printf("%d\n",k);
    for(i=1;i<=k;i++) printf("%d ",a[i]);
}