#include <bits/stdc++.h>   using namespace std;   void solve(int x, int y, int n) {     vector<int> ans(n + 1);     ans[x] = 1;     ans[y] = 2;     for (int i = 1, j = 3; i <= n; i++) {       if (ans[i] == 0) {         ans[i] = j++;       }     }     for (int i = 1; i <= n; i++) {       cout << ans[i] <<    ;     }     cout <<   n ;     ans[y] = 1;     for (int i = 1; i <= n; i++) {       cout << ans[i] <<    ;     }     cout <<   n ;     exit(0);   }   signed main() {     ios::sync_with_stdio(0);     cin.tie(0);     int n, m;     cin >> n >> m;     if (n == 0 || n * (n - 1) / 2 == m) {       cout <<  NO n ;     } else {       cout <<  YES n ;       set<pair<int, int>> st;       for (int i = 0; i < m; i++) {         int x, y;         cin >> x >> y;         if (x > y) swap(x, y);         st.insert({x, y});       }       for (int i = 1; i <= n; i++) {         for (int j = i + 1; j <= n; j++) {           if (st.find({i, j}) == st.end()) {             solve(i, j, n);           }         }       }     }     return 0;   }   