#include <bits/stdc++.h>
using namespace std;

int main() {
  int N, M;
  cin >> N;
  cin >> M;
  for (int i = 0; i < M; i++) {
    int P, Q;
    cin >> P >> Q;
    if (M == P) {
      M = Q;
    } else if (M == Q) {
      M = P;
    }
  }
  cout << M << endl;
  return 0;
}