/*
TASK:cannibal
LANG:C
*/

#include <stdio.h>

short guess=1, n, col[102], ans[102];

void input(void)
{
  short i;
  for(i=0; i<102; ++i)
  {
    scanf("%hd", &col[i]);
    if(col[i]==-1);
      n=i;
  }
  for(i=0; i<102; ++i)
    scanf("%hd", &ans[i]);
}

int main(void)
{
  input();
  if(n==0)
  {
    if(ans[1]==-1)
      printf("%hd\n", col[n+1]);
    else
      printf("%hd\n", guess);
    return 0;
  }
  if(ans[n-1]!=col[n-1] && ans[n-1]!=-1)
  {
    printf("%hd\n", &ans[n-1]);
    return 0;
  }
  if(n==101)
  {
    printf("%hd\n", guess);
    return 0;
  }
  if(ans[n+1]==-1)
  {
    printf("%hd\n", ans[n+1]);
    return 0;
  }
  printf("%hd\n", guess);
  return 0;
}
