#include<iostream>
#include<algorithm>

using namespace std;
const int N=100005;
struct node
{

  char date;
  int nex=-1;
}noda[N];

int q,p,n;
int main()
{
    cin>>q>>p>>n;
    for(int i=0;i<n;i++)
    {
        int a,b;
        char data;
        cin>>a>>data>>b;

        noda[a]={data,b};

    }
    int l=p,r=q;
   while(r!=l)
   {
       if(l==-1)l=q;
       if(r==-1) r=p;

       l=noda[l].nex;
       r=noda[r].nex;



   }
   cout<<l;


    return 0;
}