#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define all(aaa) aaa.begin(), aaa.end()
struct Seg {
int l, r, i;
};
const int N = 2e5 + 5;
vector<Seg> v;
int dp[N], w[N], nt[N];
string ans;
signed main() {
#ifdef HOME
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
for (int i = 0; i < m; i++) {
int a, b;
cin >> a >> b;
v.push_back({ a - 1, b - 1, i });
}
int x = -1, mx_len = 0;
for (int i = 0; i < m; i++) {
int len;
if (v[i].l <= v[i].r)
len = v[i].r - v[i].l + 1;
else
len = m - v[i].l + 1 + v[i].r;
if (len > mx_len) {
mx_len = len;
x = i;
}
}
int b = v[x].l, id = v[x].i;
for (int i = 0; i < m; i++) {
v[i].l = (v[i].l - b + n) % n;
v[i].r = (v[i].r - b + n) % n;
w[v[i].l]++;
w[v[i].r + 1]--;
if (v[i].l > v[i].r) {
w[0]++;
v[i].r += n;
}
}
for (int i = 0; i < n; i++) {
w[i + 1] += w[i];
if (w[i] < 2) {
cout << "impossible";
return 0;
}
}
for (int i = n - 1, j = n; i >= 0; i--) {
if (w[i] < 3)
j = i;
nt[i] = j;
}
// for (int i = 0; i < n; i++) {
// cout << w[i];
// }
// cout << "\n";
sort(all(v), [](Seg a, Seg b) {
return a.r < b.r;
});
x = 0;
while (v[x].i != id)
x++;
fill(dp, dp + m, -1);
dp[x] = -2;
set<pair<int, int>> st = { { v[x].r, x } };
for (int i = x + 1; i < m; i++) {
auto it = st.lower_bound({ v[i].l - 1, -1 });
if (it != st.end() && it->first == v[i].l - 1) {
dp[i] = it->second;
}
else {
it = st.lower_bound({ v[i].l, -1 });
if (it != st.end() && it->first < nt[v[i].l]) {
dp[i] = it->second;
}
}
if (dp[i] != -1) {
st.insert({ v[i].r, i });
}
}
int y = -1;
for (int i = 0; i < m; i++) {
if (dp[i] != -1 && (v[i].r == n - 1 || v[i].r >= n && v[i].r % n < nt[0])) {
y = i;
break;
}
}
if (y == -1) {
cout << "impossible";
return 0;
}
vector<Seg> part;
while (y >= 0) {
part.push_back(v[y]);
y = dp[y];
}
reverse(all(part));
if (part.size() > 2 && part.back().r >= n &&
part.back().r % n >= part[1].l - 1) {
part.erase(part.begin());
}
ans.resize(m, '0');
for (Seg s : part) {
ans[s.i] = '1';
}
cout << ans;
return 0;
}
