func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<vector<long long int> > edge(100010);   long long int vis[100010];   vector<long long int> color[2];   bool dfs(long long int a, long long int c = 2) {     vis[a] = c;     color[c - 1].push_back(a);     for (auto x : edge[a]) {       if (!vis[x] && dfs(x, 3ll - c)) {         return 1;       }       if (vis[x] != 3ll - c) {         return 1;       }     }     return 0;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long int n, m, x, y;     cin >> n >> m;     for (long long int i = 1; i <= m; i++) {       cin >> x >> y;       edge[x].push_back(y);       edge[y].push_back(x);     }     for (long long int i = 1; i <= n; i++) {       if (!vis[i]) {         if (edge[i].size() == 0) {           continue;         }         if (dfs(i)) {           cout << -1 << endl;           return 0;         }       }     }     for (long long int i = 0; i < 2; i++) {       cout << color[i].size() << endl;       for (auto x : color[i]) {         cout << x <<    ;       }       cout << endl;     }     return 0;   }   