#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock().now().time_since_epoch().count());
long double P(int old, int nw, long double temp) {
if(nw < old)return 1.0;
return exp((old-nw)/temp);
}
vector<int> mask;
vector<pair<int,int>> a;
int n, m;
int eval() {
int cnt1[n+1], cnt2[n+1];
memset(cnt1, 0, sizeof cnt1);
memset(cnt2, 0, sizeof cnt2);
for(int i = 0;i<m;i++) {
if(mask[i]) {
if(a[i].second>=a[i].first) {
cnt1[a[i].first]++;
cnt1[a[i].second+1]--;
}
else {
cnt1[a[i].first]++;
cnt1[0]++;
cnt1[a[i].second+1]--;
}
}
else {
if(a[i].second>=a[i].first) {
cnt2[a[i].first]++;
cnt2[a[i].second+1]--;
}
else {
cnt2[a[i].first]++;
cnt2[0]++;
cnt2[a[i].second+1]--;
}
}
}
for(int i = 1;i<=n;i++) {
cnt1[i]+=cnt1[i-1];
cnt2[i]+=cnt2[i-1];
}
int cc=0;
for(int i = 0;i<n;i++) {
if(cnt1[i]<=0 or cnt2[i]<=0)cc++;
}
return cc;
}
int main () {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m;
mask.resize(m);
a.resize(m);
for(int i = 0;i<m;i++){
cin >> a[i].first >> a[i].second;
a[i].first--;
a[i].second--;
}
for(int _ = 0;_<100;_++) {
long double temp = 100;
for(int i = 0;i<m;i++)mask[i]=rng()%2;
int old = eval();
for(int __ = 0;__<100000;__++) {
int c = rng()%m;
mask[c]^=1;
int nw = eval();
if(nw==0) {
for(int i:mask)cout << i;
cout << "\n";
return 0;
}
long double rn = (long double)(rng()%1000)/1000;
if(P(old, nw, temp)>rn) {
old=nw;
}
else {
mask[c]^=1;
}
temp*=0.95;
}
// cerr << fixed << setprecision(5) << (long double)temp << endl;
}
cout << "impossible\n";
}
