#include <bits/stdc++.h>
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define compress(v) sort(all(v)), v.erase(unique(all(v)), v.end())
using namespace std;
typedef long long ll;
int par[101010];
vector<int> g[101010];
int find(int v){ return v == par[v] ? v : par[v] = find(par[v]); }
void merge(int pa, int ch){ pa = find(pa); ch = find(ch); if(pa != ch) par[ch] = pa; }
struct Seg{
int tree[1 << 18], tmp[1 << 18], n;
void init(int _n){ n = _n; memset(tree, 0, sizeof tree); memset(tmp, 0, sizeof tree); }
void push(int node, int s, int e){
if(!tmp[node]) return;
tree[node] += tmp[node];
if(s != e){
tmp[node << 1] += tmp[node];
tmp[node << 1 | 1] += tmp[node];
}
tmp[node] = 0;
}
void update(int node, int s, int e, int l, int r, int v){
push(node, s, e);
if(r < s || e < l) return;
if(l <= s && e <= r){
tmp[node] += v; push(node, s, e);
return;
}
int m = s + e >> 1;
update(node << 1, s, m, l, r, v);
update(node << 1 | 1, m+1, e, l, r, v);
tree[node] = min(tree[node << 1], tree[node << 1 | 1]);
}
int query(int node, int s, int e, int l, int r){
push(node, s, e);
if(r < s || e < l) return 1e9;
if(l <= s && e <= r) return tree[node];
int m = s + e >> 1;
int t1 = query(node << 1, s, m, l, r);
int t2 = query(node << 1 | 1, m+1, e, l, r);
return min(t1, t2);
}
void update(int s, int e, int x){
if(e >= n) e -= n;
if(s <= e) update(1, 0, n-1, s, e, x);
else update(1, 0, n-1, 0, e, x), update(1, 0, n-1, s, n-1, x);
}
int query(){ return query(1, 0, n-1, 0, n-1); }
} seg[2];
struct Info{
int s, e, x, eli, color;
Info() : Info(0, 0, 0) {}
Info(int s, int e, int x) : s(s), e(e), x(x), eli(-1), color(-1) {}
bool operator < (const Info &t) const { return make_pair(s, -e) < make_pair(t.s, -t.e); }
};
int n, m, ed, ed_idx;
Info a[101010];
vector<Info> v;
int tmp[101010];
void calc_elimination(){
deque<Info> dq;
sort(a+1, a+m+1);
for(int i=1; i<=m; i++){
if(dq.empty() || dq.back().e < a[i].e) dq.push_back(a[i]);
else tmp[a[i].x] = dq.back().x;
}
while(dq.size() && dq.front().e <= ed) tmp[dq[0].x] = ed_idx, dq.pop_front();
for(auto i : dq) v.push_back(i);
for(int i=1; i<=m; i++) if(tmp[a[i].x]) a[i].eli = tmp[a[i].x];
iota(par, par+101010, 0);
for(int i=1; i<=m; i++) if(a[i].eli != -1) merge(a[i].eli, a[i].x);
for(int i=1; i<=m; i++){
if(a[i].eli != -1) a[i].eli = find(a[i].x), g[a[i].eli].push_back(a[i].x);
else g[a[i].x].push_back(a[i].x);
}
}
inline bool eval(){ return seg[0].query() > 0 && seg[1].query() > 0; }
void even(){
seg[0].init(n); seg[1].init(n);
for(int i=0; i<v.size(); i++) a[v[i].x].color = i % 2;
for(int i=1; i<=m; i++) if(a[i].color == -1) a[i].color = !a[a[i].eli].color;
for(int i=1; i<=m; i++){
seg[a[i].color].update(a[i].s, a[i].e, 1);
}
if(eval()){
for(int i=1; i<=m; i++) cout << a[i].color;
}
else cout << "impossible";
}
void odd(){
seg[0].init(n); seg[1].init(n);
for(int i=0; i<v.size(); i++) a[v[i].x].color = i % 2;
for(int i=1; i<=m; i++) if(a[i].color == -1) a[i].color = !a[a[i].eli].color;
for(int i=1; i<=m; i++){
seg[a[i].color].update(a[i].s, a[i].e, 1);
}
if(eval()){ for(int j=1; j<=m; j++) cout << a[j].color; return; }
for(int i=0; i<v.size(); i++){
for(auto j : g[v[i].x]){
seg[a[j].color].update(a[j].s, a[j].e, -1);
a[j].color ^= 1;
seg[a[j].color].update(a[j].s, a[j].e, 1);
}
if(eval()){ for(int j=1; j<=m; j++) cout << a[j].color; return; }
}
cout << "impossible";
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m;
for(int i=1; i<=m; i++){
int s, e; cin >> s >> e; s--; e--;
if(s > e){
if(ed < e) ed = e, ed_idx = i;
e += n;
}
a[i] = {s, e, i};
}
calc_elimination();
sort(a+1, a+m+1, [](Info a, Info b){ return a.x < b.x; });
if(v.size() % 2 == 0) even();
else odd();
}
