#include <bits/stdc++.h>
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define REV(i, b, a) for(int i = (b); i >= (a); --i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define ll long long
#define fi first
#define se second
#define BIT(x, i) ((x) >> (i) & 1)
using namespace std;
const int N = 1e5 + 5;
int n, m;
struct dizi {
int l, r, id;
bool operator < (const dizi& o) const {
int sza = r - l;
if (l > r) sza += n;
int szb = o.r - o.l;
if (o.l > o.r) szb += n;
return sza > szb;
}
} seg[N];
vector<int> v[N];
bool in[N];
vector<int> adj[N];
int col[N], ans[N];
bool chk(int v, int c = 1) {
if (col[v]) return col[v] == c;
col[v] = c;
for (auto& x : adj[v]) {
if (!chk(x, 3 - c)) return false;
}
return true;
}
void solve(int tc) {
cin >> n >> m;
set<int> se;
for (int i = 0; i < n; i++) se.insert(i);
for (int i = 0; i < m; i++) {
cin >> seg[i].l >> seg[i].r;
seg[i].l--, seg[i].r--;
seg[i].id = i;
}
sort(seg, seg + m);
for (int i = 0; i < m; i++) {
int l = seg[i].l, r = seg[i].r;
vector<int> rem;
if (l <= r) {
auto x = se.lower_bound(l);
auto y = se.upper_bound(r);
for (; x != y; x++) {
v[*x].push_back(i);
if ((int)v[*x].size() == 3) rem.push_back(*x);
}
} else {
auto x = se.lower_bound(l);
for (; x != se.end(); x++) {
v[*x].push_back(i);
if ((int)v[*x].size() == 3) rem.push_back(*x);
}
x = se.begin();
auto y = se.upper_bound(r);
for (; x != y; x++) {
v[*x].push_back(i);
if ((int)v[*x].size() == 3) rem.push_back(*x);
}
}
for (auto& x : rem) se.erase(x);
}
for (int i = 0; i < n; i++) {
if ((int)v[i].size() <= 1) {
cout << "impossible\n";
return;
}
}
for (int i = 0; i < n; i++) {
if ((int)v[i].size() == 2) {
in[v[i][0]] = in[v[i][1]] = 1;
adj[v[i][0]].push_back(v[i][1]);
adj[v[i][1]].push_back(v[i][0]);
}
}
for (int i = 0; i < m; i++) {
if (in[i] && !col[i]) {
if (!chk(i)) {
cout << "impossible\n";
return;
}
}
cout << col[i] - 1;
}
return;
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
// file("A") else file("task");
int tc = 1;
// cin >> tc;
for(int i = 1; i <= tc; ++i) solve(i);
return (0);
}
