#include <bits/stdc++.h>
using namespace std;
#define pb push_back
const int N=100050;
const int M=2*N;
const int inf=1e9+7;
int ls[M],rs[M],tsz,root,lzy[M],mn[M],n,m;
void Set(int &c, int ss, int se, int qs, int qe, int f)
{
if(qs>se || ss>qe) return;
if(!c) c=++tsz;
if(qs<=ss && qe>=se){ lzy[c]+=f;mn[c]+=f;return;}
int mid=ss+se>>1;
Set(ls[c],ss,mid,qs,qe,f);
Set(rs[c],mid+1,se,qs,qe,f);
mn[c]=min(mn[ls[c]],mn[rs[c]])+lzy[c];
}
void Set(int l, int r, int f)
{
if(l>r)
{
Set(root,1,n,1,r,f);
Set(root,1,n,l,n,f);
}
else Set(root,1,n,l,r,f);
}
int Get(int c, int ss, int se, int qs, int qe)
{
if(qs>se || ss>qe) return inf;
if(qs<=ss && qe>=se) return mn[c];
int mid=ss+se>>1;
return min(Get(ls[c],ss,mid,qs,qe),Get(rs[c],mid+1,se,qs,qe))+lzy[c];
}
int Get(int l, int r)
{
if(l>r) return min(Get(root,1,n,1,r),Get(root,1,n,l,n));
return Get(root,1,n,l,r);
}
int l[N],r[N];
vector<int> events[N],E[N];
void AddEdge(int u, int v){ E[u].pb(v);E[v].pb(u);}
int col[N];
bool was[N];
void DFS(int u)
{
was[u]=1;
for(int v:E[u])
{
if(!was[v])
{
col[v]=col[u]^1;
DFS(v);
}
else if(col[u]==col[v])
{
printf("impossible\n");
exit(0);
}
}
}
int main()
{
scanf("%i %i",&n,&m);
set<int> active;
for(int i=1;i<=m;i++)
{
scanf("%i %i",&l[i],&r[i]);
events[l[i]].pb(i);
events[r[i]+1].pb(i);
if(l[i]>r[i]) active.insert(i);
}
for(int i=1;i<=n;i++)
{
for(int j:events[i])
{
if(active.count(j)) active.erase(j);
else active.insert(j);
}
if(active.size()<2) return 0*printf("impossible\n");
if(active.size()==2) AddEdge(*active.begin(),*active.rbegin());
}
for(int i=1;i<=m;i++) if(!was[i]) DFS(i);
for(int i=1;i<=m;i++) if(!col[i]) Set(l[i],r[i],1);
for(int i=1;i<=m;i++)
{
if(col[i]) printf("0");
else
{
if(Get(l[i],r[i])==1) printf("1");
else
{
printf("0");
Set(l[i],r[i],-1);
}
}
}
return 0;
}
