#include <cstdio>

inline void read(int &sum){

  register char ch=getchar();bool symbol=;

  for(sum=;ch<''||ch>'';ch=getchar())if(ch=='-')symbol=;

  for(;ch>=''&&ch<='';sum=(sum<<)+(sum<<)+ch-'',ch=getchar());

  if(symbol)sum=-sum;

}

const int C=;

const int N=;

int fight[C][C],get[C][C][C];

int n,c;

int a[N],qian[N],hou[N],val[N],Num,size[C];

int main(){

  read(c),read(n);

  Num=c;

  for(int i=;i<=c;i++)

    for(int j=;j<=c;j++)

      read(fight[i][j]);

  for(int i=;i<=n;i++)

    read(a[i]),size[a[i]]++;

  qian[]=,hou[]=;

  for(int i=;i<=n;i++)

    qian[i+]=i,hou[i]=i+,val[i]=;

  for(int k=;k<=c;k++)

    for(int i=;i<=c;i++)

      for(int j=;j<=c;j++)

        get[k][i][j]=fight[k][i]+fight[k][j];

  while(Num!=){

    for(int i=hou[];i<=n;i=hou[i])

      val[i]+=get[a[i]][a[qian[i]]][a[hou[i]]];

    for(int i=hou[];i<=n;i=hou[i])

      if(val[i]<=){

        size[a[i]]--;

        if(!size[a[i]])Num--;

        qian[hou[i]]=qian[i];

        hou[qian[i]]=hou[i];

      }

  }

  printf("%d",a[hou[]]);

  return ;

}