// ~ Be Name Khoda ~
// Harf ke nazanim...
// Zende bemoonim?
// Ya oonm na?
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define mp make_pair
#define all(x) x.begin(), x.end()
#define fi first
#define se second
const int maxn = 1e6 + 10;
const int maxn5 = 5e5 + 10;
const int maxnt = 1.2e6 + 10;
const int maxn3 = 1e3 + 10;
const int mod = 1e9 + 7;
const ll inf = 1e18;
int a[maxn5], b[maxn5];
bool have[2][maxn5];
int n, m;
bool ty[maxn5], mark[maxn5];
vector <int> seg[maxn5], ex;
inline void solve(){
for(int i = 0; i < n; i++)
seg[i].clear();
ex.clear();
for(int i = 0; i < m; i++) if(!mark[i]){
seg[a[i] > b[i] ? 0 : a[i]].pb(i);
}
int id1 = -1, id2 = -1;
for(int i = 0; i < n; i++){
if(id1 != -1 && b[id1] < i)
id1 = -1;
if(id2 != -1 && b[id2] < i)
id2 = -1;
//cout << "here we go " << i << ' ' << id1 << ' ' << id2 << ' ' << have[1][i] << ' ' << have[0][i] << endl;
while(!ex.empty() && b[ex.back()] < i)
ex.pop_back();
for(auto u : seg[i])
ex.pb(u);
if(id1 == -1 && !have[1][i]){
if(ex.empty())
return;
id1 = ex.back();
ty[id1] = true;
ex.pop_back();
}
while(!ex.empty() && b[ex.back()] < i)
ex.pop_back();
if(id2 == -1 && !have[0][i]){
if(ex.empty())
return;
id2 = ex.back();
ty[id2] = false;
ex.pop_back();
}
}
for(int i = 0; i < m; i++)
cout << ty[i];
cout << endl;
exit(0);
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> m;
for(int i = 0; i < m; i++){
cin >> a[i] >> b[i];
a[i]--;
b[i]--;
}
int blid = -1;
for(int i = 0; i < m; i++) if(a[i] == 0 || a[i] > b[i])
if(blid == -1 || a[blid] == 0 || a[blid] > a[i])
blid = i;
if(blid == -1){
cout << "impossible\n";
return 0;
}
//cout << "ok " << blid << endl;
for(int i = 0; i < m; i++) if(i != blid && (a[i] == 0 || a[i] > b[i])){
//cout << "check out " << i << ' ' << "wtf " << blid << endl;
memset(mark, false, sizeof mark);
mark[i] = true; ty[i] = 0; mark[blid] = true; ty[blid] = 1;
memset(have, false, sizeof have);
for(int j = a[i]; j != b[i]; j = (j + 1) % n)
have[0][j] = true;
have[0][b[i]] = true;
int rbl = b[blid];
for(int j = 0; j < m; j++) if(a[j] > b[j] && (a[i] == 0 || a[j] < a[i])){
mark[j] = true; ty[j] = 1;
rbl = max(rbl, b[j]);
//cout << "blue forces " << j << endl;
}
for(int j = a[blid]; j != rbl; j = (j + 1) % n)
have[1][j] = true;
have[1][rbl] = true;
solve();
}
cout << "impossible" << '\n';
}
