#include<bits/stdc++.h>
using namespace std; using ll = long long;
const ll N = 1e5 + 3, M = N;
int opposite[M]; // 없으면 0, 있으면 번호
int c[2*N]; // 해당 영역의 colored 여부
ll n, m;
vector<array<ll,3>> Ranges;
int bit[M]; // 현재 red:1, blue:2
template <const ll N>
struct disjoint_set {
ll p[N], s[N];
disjoint_set() { iota(p,p+N,0), fill(s,s+N,1); }
ll find(ll x) {
assert(x < N);
if (x == p[x]) return x;
return p[x] = find(p[x]);
}
void merge(ll b, ll a) {
a = find(a), b = find(b);
if (a==b) return;
s[b] += s[a], p[a] = b;
}
ll size(ll x) {
return s[find(x)];
}
bool same(ll a, ll b) {
return find(a) == find(b);
}
};
disjoint_set<M> dsu;
struct segtree {
struct node {
int v;
int z;
node(): v(0), z(0) {}
} t[N<<2];
void push(int k, int s, int e) {
t[k].v+=t[k].z;
if (s!=e) {
t[2*k].z+=t[k].z;
t[2*k+1].z+=t[k].z;
}
t[k].z=0;
}
void add(int l, int r, int v, int k=1, int s=1, int e=n) {
push(k,s,e);
if (e<l||r<s) return;
if (l<=s&&e<=r) {t[k].z+=v, push(k,s,e); return;}
int m=(s+e)>>1;
add(l,r,v,2*k,s,m);
add(l,r,v,2*k+1,m+1,e);
t[k].v=min(t[2*k].v, t[2*k+1].v);
}
int qry(int l, int r, int k=1, int s=1, int e=n) {
push(k,s,e);
if (e<l||r<s) return 1e9;
if (l<=s&&e<=r) return t[k].v;
int m=(s+e)>>1;
return min(qry(l,r,2*k,s,m), qry(l,r,2*k+1,m+1,e));
}
} Red, Blue;
void solve() {
for (ll k=0; auto [l,r,name] : Ranges) {
k++;
if (k&1) {
bit[name]=1;
if (r<=n) Red.add(l,r,1);
else Red.add(l,n,1), Red.add(1,r-n,1);
}
else {
bit[name]=2;
if (r<=n) Blue.add(l,r,1);
else Blue.add(l,n,1), Blue.add(1,r-n,1);
}
}
auto good = []() {
return Red.qry(1,n) > 0 && Blue.qry(1,n) > 0;
};
if (good()) return;
auto red_to_blue = [](int l, int r) {
if (r<=n) {
Red.add(l,r, -1);
Blue.add(l,r, +1);
}
else {
Red.add(l,r-n, -1);
Blue.add(l,r-n, +1);
Red.add(1,r, -1);
Blue.add(1,r, +1);
}
};
auto blue_to_red = [](int l, int r) {
if (r<=n) {
Blue.add(l,r, -1);
Red.add(l,r, +1);
}
else {
Blue.add(l,r-n, -1);
Red.add(l,r-n, +1);
Blue.add(1,r, -1);
Red.add(1,r, +1);
}
};
for (ll k=0; auto [l,r,name] : Ranges) {
k++;
if (k&1) {
bit[name]=2;
red_to_blue(l,r);
if (good()) return;
}
else {
bit[name]=1;
blue_to_red(l,r);
if (good()) return;
}
}
cout << "impossible";
exit(0);
}
int main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n >> m;
vector<array<ll,3>> R;
for(ll i=1; i<=m; ++i) {
int l, r; cin >> l >> r;
if (l-1 == r) {
R.push_back({1,2*n,i});
}
else if (l > r) {
R.push_back({l,r+n, i});
}
else {
R.push_back({l,r, i});
R.push_back({l+n,r+n, i});
}
}
sort(begin(R),end(R),[](auto &x, auto &y) {
if (x[0]==y[0]) return x[1]>y[1];
return x[0]<y[0];
});
auto cmp = [](const array<ll,3> &x, const array<ll,3> &y) {
if (x[1] != y[1]) return x[1] > y[1];
return x[2] < y[2]; // 모든 range의 이름은 구분되기 때문에..
};
set<array<ll,3>,decltype(cmp)> reduced_ranges;
for(ll i=0; i<size(R); ++i) {
if (!empty(reduced_ranges) && R[i][1] <= reduced_ranges.begin()->at(1)) {
c[R[i][0]]++;
c[R[i][1]+1]--;
opposite[R[i][2]] = reduced_ranges.begin()->at(2);
}
else if (!opposite[R[i][2]]) {
reduced_ranges.insert(R[i]);
}
}
for(ll i=1; i<=2*n; ++i) {
c[i] += c[i-1];
if (i>n && c[i]) {
c[i-n]=1;
}
}
for(ll i=1; i<=n; ++i) {
c[i]=(c[i]>0);
if (c[i]) Red.add(i,i,+1), Blue.add(i,i,+1);
}
for (auto [l,r,k] : reduced_ranges) {
if (l>n&&r>n) {
Ranges.push_back({l-n,r-n,k});
}
else {
Ranges.push_back({l,r,k});
}
}
ranges::sort(Ranges);
Ranges.erase(unique(Ranges.begin(),Ranges.end()),end(Ranges));
solve();
for (ll i=1; i<=m; ++i) if (opposite[i]) {
dsu.merge(opposite[i], i);
}
for(ll i=1; i<=m; ++i) {
if (bit[i]) {
cout << bit[i]-1;
}
else {
assert(opposite[i]);
cout << (bit[dsu.find(i)]%2);
}
}
}
