#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define pb push_back
#define vi vector<int>
#define vl vector<ll>
#define pi pair<int, int>
#define pl pair<ll,ll>
#define all(x) (x).begin(),(x).end()
bool con(int a, int b, int c, int d, int m) {
if (b<a) {
return (con(a,m-1,c,d,m)&con(0,b,c,d,m));
}
else if (d<c) {
return (con(a,b,c,m-1,m)|con(a,b,0,d,m));
}
return (c<=a && b<=d);
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n,m;
cin >> n >> m;
vector<pi> inte(m);
for (int i=0; i<m; i++) {
cin >> inte[i].fi >> inte[i].se;
inte[i].fi--;
inte[i].se--;
if ((inte[i].se+1)%n==inte[i].fi) {
inte[i]={0,n-1};
}
}
vi col(m,-1);
vi inv_of(m,-1);
vector<vi> to(m);
vi rem;
for (int i=0; i<m; i++) {
if (col[i]!=-1) {
continue;
}
for (int j=0; j<m; j++) {
if (i==j) {
continue;
}
if (inte[i]==inte[j]) {
col[i]=1;
col[j]=0;
break;
}
}
if (col[i]!=-1) {
continue;
}
for (int j=0; j<m; j++) {
if (i==j) {
continue;
}
if (con(inte[i].fi,inte[i].se,inte[j].fi,inte[j].se,n)) {
inv_of[i]=j;
to[j].pb(i);
break;
}
}
if (inv_of[i]==-1) {
rem.pb(i);
}
}
sort(all(rem),[&](int a, int b){return inte[a].fi<inte[b].fi;});
if (rem.size()%2==0) {
for (int i=0; i<rem.size(); i++) {
col[rem[i]]=i%2;
}
for (int i=0; i<m; i++) {
if (inv_of[i]!=-1) {
continue;
}
queue<pi> q;
q.push({i,col[i]});
while (q.size()) {
auto [a,c]=q.front();
q.pop();
col[a]=c;
for (auto t:to[a]) {
q.push({t,c^1});
}
}
}
vi a(n+1,0),b(n+1,0);
for (int i=0; i<m; i++) {
if (col[i]) {
if (inte[i].fi<=inte[i].se) {
a[inte[i].fi]++;
a[inte[i].se+1]--;
}
else {
a[inte[i].fi]++;
a[n]--;
a[0]++;
a[inte[i].se+1]--;
}
}
else {
if (inte[i].fi<=inte[i].se) {
b[inte[i].fi]++;
b[inte[i].se+1]--;
}
else {
b[inte[i].fi]++;
b[n]--;
b[0]++;
b[inte[i].se+1]--;
}
}
}
for (int i=0; i<n; i++) {
if (i>0) {
a[i]+=a[i-1];
b[i]+=b[i-1];
}
if (a[i]==0 || b[i]==0) {
cout << "impossible\n";
return 0;
}
}
for (int i=0; i<m; i++) {
cout << col[i];
}
cout << '\n';
}
else {
for (int i=0; i<rem.size(); i++) {
col[rem[i]]=0;
for (int j=i; j!=(i+1)%rem.size(); j=(j+2)%rem.size()) {
col[rem[j]]=0;
}
for (int j=(i+1)%rem.size(); j!=i; j=(j+2)%rem.size()) {
col[rem[j]]=1;
}
for (int i=0; i<m; i++) {
if (inv_of[i]!=-1) {
continue;
}
queue<pi> q;
q.push({i,col[i]});
while (q.size()) {
auto [a,c]=q.front();
q.pop();
col[a]=c;
for (auto t:to[a]) {
q.push({t,c^1});
}
}
}
vi a(n+1,0),b(n+1,0);
for (int i=0; i<m; i++) {
if (col[i]) {
if (inte[i].fi<=inte[i].se) {
a[inte[i].fi]++;
a[inte[i].se+1]--;
}
else {
a[inte[i].fi]++;
a[n]--;
a[0]++;
a[inte[i].se+1]--;
}
}
else {
if (inte[i].fi<=inte[i].se) {
b[inte[i].fi]++;
b[inte[i].se+1]--;
}
else {
b[inte[i].fi]++;
b[n]--;
b[0]++;
b[inte[i].se+1]--;
}
}
}
bool ok=1;
for (int i=0; i<n; i++) {
if (i>0) {
a[i]+=a[i-1];
b[i]+=b[i-1];
}
if (a[i]==0 || b[i]==0) {
ok=0;
}
}
if (!ok) {
continue;
}
for (int i=0; i<m; i++) {
cout << col[i];
}
cout << '\n';
return 0;
}
cout << "impossible\n";
}
return 0;
}
