const int maxn = 2e5 + ;

 int n, m, color[maxn];

 vector<int> vc[maxn];

 vector<P> e;

 void dfs(int cur, int co) {

     color[cur] = co;

     for (auto i : vc[cur]) {

         if (!color[i]) {

             dfs(i,  - co);

         } else if (color[i] == color[cur]) {

             puts("NO");

             exit();

         }

     }

 }

 int main() {

     read(n), read(m);

     rep(i, , m) {

         int u, v;

         read(u), read(v);

         vc[u].push_back(v);

         vc[v].push_back(u);

         e.push_back({u, v});

     }

     dfs(, );

     puts("YES");

     for (auto i : e) {

         write(color[i.first] < color[i.second]);

     }

     return ;

 }