#include <iostream>
using namespace std;

int main() {
    int n, m, p, q, t;
    cin >> n >> m;
    int c[3] = {};
    c[n - 1] = 1;
    while (m--) {
        cin >> p >> q;
        t = c[p - 1];
        c[p - 1] = c[q - 1];
        c[q - 1] = t;
    }
    int ans = -1;
    for (int i = 0; i < 3; i++) {
        if (c[i] == 1) {
            ans = i + 1;
            break;
        }
    }
    cout << ans << endl;
}