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

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