#include<iostream>
#include<cstdio>
#include<vector>
#include<cmath>
#define N 2001
#define M 15
#define K 100000
#define W 992
#define inf 1e8
using namespace std;
int read()
{
	char c=0;
	int sum=0;
	while (c<'0'||c>'9') c=getchar();
	while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
	return sum;
}
struct reads
{
	int x,y;
};
reads tong[K+1];
int n,k,length,dp[M+1][W+1][N+1],ps[M+1][W+1][N+1],ps2[M+1][W+1][N+1],pst[M+1][W+1][N+1],F[N+1],F2[N+1],maxn[M+1]={0,0,0,31,320,276,992,992,991,990,989,988,987,986,985,984};
void adder(int x,int y)
{
	tong[++length]=(reads){x,y};
	return;
}
void calc()
{
	for (int i=1;i<=n;++i) F[i]=i-1,F2[i]=(i-1)<<1;
	for (int i=0;i<=k;++i)
		for (int j=0;j<=min(W,n);++j)
			for (int t=0;t<=n;++t)
				dp[i][j][t]=inf;
	dp[0][0][0]=dp[0][0][1]=dp[1][0][0]=0;
	for (int i=1;i<=n;++i) dp[1][0][i]=((i*(i-1))>>1)-(i-1);
	for (int i=2;i<=k;++i)
		for (int j=0;j<=n;++j)
		{
			if (j<=i+1) dp[i][0][j]=0;
			for (int s=1;s<=min(maxn[i],j-1);++s)
			{
				if (s==1)
				{
					for (int t=(j?ps[i][s][j-1]:0);t<=j-1;++t)
						if (dp[i][0][t]+dp[i][0][j-1-t]+F[t]+F2[j-1-t]+(t!=j-1)<dp[i][s][j])
							dp[i][s][j]=dp[i][0][t]+dp[i][0][j-1-t]+F[t]+F2[j-1-t]+(t!=j-1),ps[i][s][j]=t;
				}
				else
				{
					for (int t=(j?ps[i][s][j-1]:0);t<=j-1;++t)
						if (dp[i][s-1][t]+dp[i][0][j-1-t]+F2[j-1-t]+(t!=j-1)<dp[i][s][j])
							dp[i][s][j]=dp[i][s-1][t]+dp[i][0][j-1-t]+F2[j-1-t]+(t!=j-1),ps[i][s][j]=t;
				}
				if (j!=i-1)
				{
					for (int t=(j?pst[i][s][j-1]:0);t<=j-1;++t)
						if (dp[i][s][t]+dp[i][0][j-1-t]+F[j-1-t]+dp[i-2][0][s+1]<dp[i][0][j])
							dp[i][0][j]=dp[i][s][t]+dp[i][0][j-1-t]+F[j-1-t]+dp[i-2][0][s+1],ps[i][0][j]=pst[i][s][j]=t,ps2[i][0][j]=s;
				}
			}
			for (int t=0;t<=j-1;++t)
				if (dp[i][0][t]+dp[i][0][j-1-t]+F[t]+F[j-1-t]<dp[i][0][j])
					dp[i][0][j]=dp[i][0][t]+dp[i][0][j-1-t]+F[t]+F[j-1-t],ps[i][0][j]=t,ps2[i][0][j]=0;
		}
	return;
}
void solve(vector<int>p,int d)
{
	if (p.size()<=d+1) return;
	if (d==1)
	{
		for (int i=0;i<p.size();++i)
			for (int j=i+2;j<p.size();++j)
				adder(p[i],p[j]);
	}
	else
	{
		int r=ps2[d][0][p.size()]+1,pst;
		vector<int>v(r+1);
		vector<int>st;
		pst=ps[d][0][p.size()],v[r]=pst+1;
		for (int i=r-1;i>=1;--i) v[i]=ps[d][i][pst]+1,pst=ps[d][i][pst];
		for (int i=1;i<=r-1;++i)
			if (v[i+1]-v[i]!=1)
				adder(p[v[i]-1],p[v[i+1]-1]);
		for (int i=1;i<=r;++i) st.push_back(p[v[i]-1]);
		solve(st,d-2);
		if (1<=v[1]-1)
		{
			st.clear();
			for (int i=1;i<=v[1]-1;++i)
			{
				if (i!=v[1]-1) adder(p[i-1],p[v[1]-1]);
				st.push_back(p[i-1]);
			}
			solve(st,d);
		}
		for (int i=1;i<=r-1;++i)
			if (v[i]+1<=v[i+1]-1)
			{
				st.clear();
				for (int j=v[i]+1;j<=v[i+1]-1;++j)
				{
					if (j!=v[i]+1) adder(p[v[i]-1],p[j-1]);
					if (j!=v[i+1]-1) adder(p[j-1],p[v[i+1]-1]);
					st.push_back(p[j-1]);
				}
				solve(st,d);
			}
		if (v[r]+1<=p.size())
		{
			st.clear();
			for (int i=v[r]+1;i<=p.size();++i)
			{
				if (i!=v[r]+1) adder(p[v[r]-1],p[i-1]);
				st.push_back(p[i-1]);
			}
			solve(st,d);
		}
	}
	return;
}
int main()
{
	vector<int>p;
	n=read()+1,k=read(),calc();
	for (int i=1;i<=n;++i) p.push_back(i);
	solve(p,k),printf("%d\n",length);
	for (int i=1;i<=length;++i) printf("%d %d\n",tong[i].x-1,tong[i].y-1);
	return 0;
}