#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define ll long long
ll mod=1000000007;
int inf=1000000007;
ll infl=1000000000000000007;
void gg()
{
cout<<"impossible";
exit(0);
}
const int N=100007,pot=1<<17;
bool ans[N];
int l[N];
int r[N];
int ile[N];
int L[N];
vector<int>V[N];
int o[N];
pair<int,int> seg[2*pot+7];
pair<int,int> que(int v)
{
v+=pot-1;
pair<int,int>p={inf,0};
while(v>0)
{
p=min(p,seg[v]);
v/=2;
}
return p;
}
void ins(int v,int a,int b,int l,int r,int x,int i)
{
if(a<=l&&b>=r)
{
seg[v]=min(seg[v], {x,i});
return ;
}
if(r<a||l>b) return ;
ins(2*v,a,b,l,(l+r)/2,x,i);
ins(2*v+1,a,b,(l+r)/2+1,r,x,i);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,m;
cin>>n>>m;
int mx=0,k;
for(int i=1;i<=m;i++)
{
cin>>l[i]>>r[i];
l[i]--;
r[i]--;
if((r[i]-l[i]+n)%n+1>mx)
{
mx=(r[i]-l[i]+n)%n+1;
k=i;
}
}
ans[k]=1;
int t=l[k];
for(int i=1;i<=m;i++)
{
l[i]=(l[i]-t+n)%n;
r[i]=(r[i]-t+n)%n;
// cout<<l[i]<<" "<<r[i]<<endl;
if(l[i]<=r[i])
{
ile[l[i]]++;
ile[r[i]+1]--;
}
else
{
ile[l[i]]++;
ile[0]++;
ile[r[i]+1]--;
}
}
int act=0;
L[0]=-1;
for(int i=0;i<n;i++)
{
act+=ile[i];
if(act<2) gg();
if(i>0) L[i]=L[i-1];
if(act==2) L[i]=i;
}
for(int i=1;i<=m;i++) if(i!=k) V[l[i]].pb(i);
for(int i=1;i<2*pot;i++) seg[i].st=inf;
ins(1,L[r[k]]+2,r[k]+2,1,pot,r[k]+1,k);
int X=-1;
if(r[k]==n-1) X=k;
for(int j=0;j<n;j++)
{
for(auto i:V[j])
{
pair<int,int>p=que(l[i]+1);
o[i]=p.nd;
if(o[i]!=0&&r[i]==n-1) X=i;
if(l[i]<=r[i]) ins(1,max(p.st,L[r[i]]+1)+1,r[i]+2,1,pot,r[i]+1,i);
else
{
if(o[i]!=0&&L[r[i]]==-1) X=i;
}
}
}
if(X==-1) gg();
while(X>0)
{
ans[X]=1;
X=o[X];
}
for(int i=1;i<=m;i++) cout<<ans[i];
return 0;
}
