#include<stdio.h>
int h[251][251],g[201][201],d[30];
int main(){
	int m,n,l,i,j,k,t,a,b,ans=5000;
	scanf("%d%d%d",&m,&n,&l);
	for(i=0;i<l;i++)scanf("%d",&d[i]);
	for(i=1;i<=m;i++){
		for(j=1;j<=m;j++)g[i][j]=5000;
		g[i][i]=0;
	}
	for(i=1;i<=m;i++){
		scanf("%d%d",&j,&a);
		t=a;
		while(j---1){
			scanf("%d",&b);
			h[a][b]=i;
			if(h[b][a]&&h[b][a]!=h[a][b])g[h[b][a]][h[a][b]]=g[h[a][b]][h[b][a]]=1;
			a=b;
		}
		b=t;
		h[a][b]=i;
		if(h[b][a]&&h[b][a]!=h[a][b])g[h[b][a]][h[a][b]]=g[h[a][b]][h[b][a]]=1;
	}
	for(i=1;i<=m;i++)for(j=1;j<=m;j++)for(k=1;k<=m;k++)
		if(g[i][k]+g[k][j]<g[i][j])g[i][j]=g[i][k]+g[k][j];
	for(i=1;i<=m;i++){
		t=0;
		for(j=0;j<l;j++){
			a=5000;
			for(k=1;k<=n;k++){
				if(h[k][d[j]]&&g[h[k][d[j]]][i]<a)a=g[h[k][d[j]]][i];
				if(h[d[j]][k]&&g[h[d[j]][k]][i]<a)a=g[h[d[j]][k]][i];
			}
			t+=a;
		}
		if(t<ans)ans=t;
	}
	printf("%d\n",ans);
	return 0;
}
自己很无奈，构造了多组，都是对的...
floyd+枚举做的