#include<iostream>
#include<cstdio>
using namespace std;
const int INF=1e9;
bool flag1=0,flag2=0;
int n,m,i,p,zj1,zj2,ST,SD,ans;
int main()
{
	freopen("cowroute.in","r",stdin);
	freopen("cowroute.out","w",stdout);
	scanf("%d%d%d",&ST,&SD,&n);
	if(ST==SD)printf("0\n");
	else
	{
		ans=INF;
		for(i=1;i<=n;i++)
		{
			scanf("%d%d",&zj1,&p);
			flag1=0,flag2=0;
			while(p--)
			{
				scanf("%d",&zj2);
				if(zj2==ST)flag1=1;
				else if(zj2==SD)
					if(flag1)flag2=1;
			}
			if(flag1&&flag2)
				if(ans>zj1)ans=zj1;
		}
		if(ans==INF)printf("-1\n");
		else printf("%d\n",ans);
	}
	fclose(stdin);
	fclose(stdout);
	return 0;
}