#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <climits>
#include <numeric>
#include <iterator>
#include <cmath>
#include <set>
#include <bitset>
#include <cassert>
using namespace std;

namespace Estd {
	// return 1's position (...3210) by given bs;
	// invarient: bs.count() == 1;
	// ex: 0000100 -> 2
	template<size_t N>
	constexpr size_t position(const bitset<N> bs) {
		assert(bs.count() == 1);
		for (int i = 0; i < N; ++i) {
			if (bs[i] == 1)
				return i;
		}
		throw;
	}
};

int main() {
	int N {};
	int M {};
	cin >> N >> M;

	bitset<3> res {};
	res.set(N-1);
	for (int i = 0; i < M; ++i) {
		int p {};
		int q {};
		cin >> p >> q;

		const int fir {p-1};
		const int sec {q-1};

		if (res[fir]) {
			res.reset(fir);
			res.set(sec);
		} else if (res[sec]) {
			res.set(fir);
			res.reset(sec);
		} else {
			continue;
		}
	}
	cout << Estd::position(res) + 1 << endl;
}