#include <bits/stdc++.h>
using namespace std;

int main() {
	ios_base::sync_with_stdio (false);
	int n, m;
	cin>>n>>m;
	int min_diff = 100005;
	for (int i=0; i<n; i++) {
		int l, r;
		cin>>l>>r;
		min_diff = min (min_diff, r - l + 1);
	}
	cout<<min_diff<<endl;
	for (int i=0; i<n; i++) {
		cout<< (i%min_diff)<<" ";
	}
	cout<<endl;
	return 0;
}