#include <iostream>

#include <cstring>

#include <cstdio>

#include <vector>

#define fi first

#define se second

using namespace std;

typedef pair<int, int> PII;

const int maxn = 1e6 + ;

int du[maxn], f[maxn];

vector<PII> edges;

vector<int> G[maxn], V;

int n, m, x, y;

void dfs(int x){

    for(auto i : G[x]){

        if(f[i]) continue;

        auto e = edges[i];

        if(e.fi != x) f[i] = ;

        else f[i] = ;

        dfs(e.fi == x ? e.se : e.fi);

    }

}

int main()

{

    cin>>n>>m;

    for(int i = ; i < m; i++){

        scanf("%d %d", &x, &y);

        edges.push_back({x, y});

        G[x].push_back(i);

        G[y].push_back(i);

        du[x]++; du[y]++;

    }

    for(int i = ; i <= n; i++) if(du[i]&) V.push_back(i);

    int M = m;

    for(int i = ; i < V.size(); i += ){

        x = V[i];

        y = V[i+];

        edges.push_back({x, y});

        m++;

        G[x].push_back(m-);

        G[y].push_back(m-);

    }

    for(int i = ; i <= n; i++) dfs(i);

    cout<<n - V.size()<<endl;

    for(int i = ; i < M; i++){

        if(f[i] == ) putchar('');

        else putchar('');

    }

}