#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
#include <random>
#include <set>
using ll = long long;
#define debug(x) #x << " = " << x << '\n'
const int NMAX = 1e5 + 100;
std::vector<int> g[NMAX];
bool vis[NMAX];
bool color[NMAX];
void add_edge(int u, int v) {
g[u].push_back(v);
g[v].push_back(u);
}
bool bipartite = true;
void dfs(int u) {
vis[u] = true;
for (const auto &v : g[u]) {
if (!vis[v]) {
color[v] = 1 ^ color[u];
dfs(v);
} else {
if (color[u] == color[v]) {
bipartite = false;
}
}
}
}
int p[2][NMAX];
int root(int c, int u) {
return p[c][u] == u? u : p[c][u] = root(c, p[c][p[c][u]]);
}
int n;
void activate(int c, int u) {
p[c][u] = p[c][u + 1];
}
void add_seg(int l, int r, int c) {
int p = root(c, l);
while (p <= r) {
activate(c, p);
p = root(c, p);
}
}
void add_colored(int l, int r, int c) {
if (l <= r) {
add_seg(l, r, c);
} else {
add_seg(0, r, c);
add_seg(l, n - 1, c);
}
}
bool is_colored(int l, int r, int c) {
if (l <= r) {
return root(c, l) > r;
} else {
return root(c, l) == n && root(c, 0) > r;
}
}
struct Event {
int index;
bool add;
bool operator < (const Event &other) const {
return add < other.add;
};
};
std::mt19937 rng(123);
int main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
std::ios_base::sync_with_stdio(false);
std::cin.tie(0);
int m;
std::cin >> n >> m;
std::vector<std::pair<int, int>> a(m);
for (auto &[l, r] : a) {
std::cin >> l >> r;
l--, r--;
}
std::vector<std::vector<Event>> sweep(n + 1);
for (int i = 0; i < m; i++) {
auto [l, r] = a[i];
if (l <= r) {
sweep[l].push_back({i, true});
sweep[r + 1].push_back({i, false});
} else {
sweep[0].push_back({i, true});
sweep[r + 1].push_back({i, false});
sweep[l].push_back({i, true});
}
}
std::set<int> active;
for (int i = 0; i < n; i++) {
for (const auto &event : sweep[i]) {
if (event.add) {
active.insert(event.index);
} else {
active.erase(event.index);
}
}
if ((int) active.size() <= 1) {
std::cout << "impossible";
return 0;
} else if ((int) active.size() == 2) {
add_edge(*active.begin(), *active.rbegin());
}
}
active.clear();
for (int i = 0; i < m; i++) {
if (!vis[i] && !g[i].empty()) {
dfs(i);
}
}
if (!bipartite) {
std::cout << "impossible";
} else {
std::vector<int> order(m);
for (int i = 0; i < m; i++) {
order[i] = i;
}
while (true) {
for (int i = 0; i <= n; i++) {
p[0][i] = p[1][i] = i;
}
for (int i = 0; i < m; i++) {
if (vis[i]) {
add_colored(a[i].first, a[i].second, color[i]);
}
}
for (const auto &i : order) {
if (!vis[i]) {
auto &[l, r] = a[i];
if (!is_colored(l, r, 0)) {
color[i] = 0;
} else {
color[i] = 1;
}
add_colored(l, r, color[i]);
}
}
bool ok = true;
for (int i = 0; i < n; i++) {
if (root(0, i) == i || root(1, i) == i) {
ok = false;
}
}
if (ok) {
for (int i = 0; i < m; i++) {
std::cout << color[i];
}
return 0;
}
std::shuffle(order.begin(), order.end(), rng);
}
}
return 0;
}
