#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

bool isOrdered(const vector<int>& positions) {
	for (size_t i = 0; i < positions.size(); ++i) {
		if (positions[i] != i) {
			return false;
		}
	}
	return true;
}

int main() {
	int n, k;
	cin >> n >> k;
	vector<int> x(k), y(k);
	for (int i = 0; i < k; ++i) {
		cin >> x[i] >> y[i];
	}
	vector<int> positions(n);
	for (int i = 0; i < n; ++i) {
		positions[i] = i;
	}
	for (int i = 0; i < k; ++i) {
		swap(positions[x[i] - 1], positions[y[i] - 1]);
	}
	int result = 1;
	vector<int> values(positions);
	vector<int> newValues(n);
	while (!isOrdered(values)) {
		for (int i = 0; i < n; ++i) {
			newValues[i] = values[positions[i]];
		}
		values = newValues;
		++result;
	}
	cout << result << endl;
	return 0;
}