#include <bits/stdc++.h>
using namespace std;
/*
*/
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long double, long double> pdd;
const int MAXN = 1e5+10;
vector<int> w[MAXN];
bool ty[MAXN];
pii cb[MAXN];
int act[MAXN][2];
bool us[MAXN];
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// cout << fixed << setprecision(7);
int n, m;
cin >> n >> m;
int a, b;
vector<int> cy;
for (int i=0;i<m;i++){
cin >> a >> b;
cb[i] = {a,b};
if(b<a){
if (b==a-1){
a=1,b=n;
}else{
cy.push_back(i);
continue;
}
}
w[a].push_back(i);
w[b].push_back(i);
}
set<int> cr;
act[1][0] = act[1][1]=-1;
for (int i=1;i<=n;i++){
vector<int> rm;
while (!w[i].empty()){
int u = w[i].back();
w[i].pop_back();
if (cr.count(u) || act[i][0] == u || act[i][1]==u){
rm.push_back(u);
}else{
cr.insert(u);
}
}
if (act[i][0]==-1 && !cr.empty()){
act[i][0] = *cr.begin();
cr.erase(cr.begin());
ty[act[i][0]]=0;
}
if (act[i][1]==-1 && !cr.empty()){
act[i][1] = *cr.begin();
cr.erase(cr.begin());
ty[act[i][1]]=1;
}
act[i+1][0]=act[i][0], act[i+1][1]=act[i][1];
for (auto &u:rm){
cr.erase(u);
if (act[i][0]==u) act[i+1][0]=-1;
if (act[i][1]==u) act[i+1][1]=-1;
}
}
for (auto &x:cy){
a=cb[x].first, b = cb[x].second;
w[a].push_back(x);
}
set<pii> ac; // {esquerda, cara}
int has[2] = {-1,-1};
for (int i=1;i<=n;i++){
while (!w[i].empty()){
int u = w[i].back();
w[i].pop_back();
ac.emplace(cb[u].second, u);
}
for (int j=0;j<2;j++) if (has[j]!=-1) act[i][j]=has[j];
for (int j=0;j<2;j++){
if (act[i][j]==-1 && !ac.empty()){
int u = ac.begin()->second;
ac.erase(ac.begin());
us[u] = 1, ty[u]=j, has[j]=act[i][j]=u;
}
}
}
cr.clear();
set<int> st[2], sc;
for (auto &x:cy){
w[cb[x].second].push_back(x);
if (us[x]) st[ty[x]].insert(x);
else sc.insert(x);
}
for (int i=1;i<=n;i++){
vector<int> rm;
while (!w[i].empty()){
rm.push_back(w[i].back());
w[i].pop_back();
}
bool valid = 1;
for (int j=0;j<2;j++){
if (act[i][j]==-1 && st[j].empty()){
if (sc.empty()){
valid = 0;
break;
}
int u = *sc.begin();
sc.erase(sc.begin());
us[u]=1, ty[u]=j;
st[j].insert(u);
}
}
if (!valid){
cout << "impossible\n";
return 0;
}
for (auto &u:rm){
st[0].erase(u);
st[1].erase(u);
sc.erase(u);
}
}
for (int i=0;i<m;i++) cout << (int)ty[i];
cout << '\n';
return 0;
}
