#include<bits/stdc++.h>
#define X first
#define Y second
using namespace std;
typedef pair<int,int> pii;
const int N = 100005, inf = 1e9;
int n, m, s[N], nxt[N], opt[N];
bool non[N];
pii a[N];
vector<int> ans, in[N], out[N];
set<pii> st, ss, es;
void boom () {
puts("impossible");
exit(0);
}
void solve (vector<pair<pii, int> > &V, vector<int> &X) {
int DI;
for(auto &T : V) {
int S = T.X.X, E = T.X.Y, I = T.Y;
if(E == n) {
st.insert({S, I});
DI = I;
}
else {
int J = upper_bound(X.begin(), X.end(), E) - X.begin() - 1;
if(J < 0 || X[J] < S) J = S;
else J = X[J];
auto it = st.lower_bound({J+1, 0});
if(it != st.end() && (it->X) <= E+1) {
st.insert({S, I});
nxt[I] = (it->Y);
}
}
}
if(!nxt[DI]) boom();
ans.push_back(DI);
for(int i=nxt[DI];i!=DI;i=nxt[i]) {
ans.push_back(i);
}
}
void eliminate () {
for(auto &T : ans) {
if(a[T].X > a[T].Y) in[1].push_back(T);
out[a[T].Y+1].push_back(T);
in[a[T].X].push_back(T);
}
for(int i=1;i<=n;i++) {
for(auto &T : out[i]) {
int S = a[T].X, E = a[T].Y;
if(S > E) S -= n;
auto it = ss.find({S, T});
if(it != ss.end()) ss.erase(it);
it = es.find({E, T});
if(it != es.end()) es.erase(it);
}
for(auto &T : in[i]) {
if(non[T]) continue;
int S = a[T].X, E = a[T].Y;
if(S > E) {
if(i == 1) S -= n;
else E += n;
}
ss.insert({S, T});
es.insert({E, T});
}
if(ss.size() > 2) {
auto si = ss.begin(), ei = es.end();
ei--;
int A = si->Y, B = ei->Y;
set<pii> SS, ES;
for(auto &T : ss) {
int I = T.Y;
if(A == I || B == I) SS.insert(T);
else non[I] = true;
}
for(auto &T : es) {
int I = T.Y;
if(A == I || B == I) ES.insert(T);
else non[I] = true;
}
swap(SS, ss);
swap(ES, es);
}
}
vector<int> ANS;
for(auto &T : ans) {
if(!non[T]) ANS.push_back(T);
}
swap(ANS, ans);
}
int main()
{
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++) {
scanf("%d%d",&a[i].X,&a[i].Y);
if(a[i].X <= a[i].Y) {
s[a[i].X]++;
s[a[i].Y+1]--;
}
else {
s[1]++;
s[a[i].Y+1]--;
s[a[i].X]++;
}
}
int MV = inf, MI;
for(int i=1;i<=n;i++) {
s[i] += s[i-1];
if(MV > s[i]) {
MV = s[i];
MI = i;
}
}
if(MV < 2) boom();
else if(MV == 2) {
vector<pair<pii, int> > V, O;
vector<int> X;
for(int i=1;i<=m;i++) {
a[i].X -= MI;
a[i].Y -= MI;
if(a[i].X <= 0) a[i].X += n;
if(a[i].Y <= 0) a[i].Y += n;
if(a[i].X > a[i].Y || (a[i].X <= n && n <= a[i].Y)) {
O.push_back({{a[i].X, (a[i].Y == n ? 0 : a[i].Y)}, i});
}
else V.push_back({a[i], i});
}
V.push_back({{0, O[0].X.Y}, O[0].Y});
V.push_back({{O[0].X.X, n}, O[0].Y});
sort(V.begin(), V.end());
reverse(V.begin(), V.end());
for(int i=1;i<n;i++) {
int I = (i + MI > n ? i + MI - n : i + MI);
if(s[I] == 2) X.push_back(i);
}
solve(V, X);
}
else {
for(int i=1;i<=m;i++) {
ans.push_back(i);
}
}
eliminate();
for(auto &T : ans) {
opt[T] = 1;
}
for(int i=1;i<=m;i++) {
printf("%d",opt[i]);
}
}
