#include <assert.h>
#include <cstdio>
#include <cmath>
using namespace std;

#if !LOCALTEST
#undef assert
#define assert(...) (void)0
#endif

#define T 3600
#define N 5400

int const di[]={0,464,1008,1624,2296,3046,3842,4820,5869,7124,8444,9893,11469,13291,15269,17464,19858,22407,25211,28244,31439,34949,38849,42929,47339,52089,57066,62394,68005,73919,80095,86765,93683,100855,108417,116283,124706,133132,141979,151078,160492,170288,180096,190140,200423,210928,221280,232133,242922,253760,264610,275390,286240,297078,307867,318720,329072,339577,349860,359904,369712,379508,388922,398021,406868,415294,423717,431583,439145,446317,453235,459905,466081,471995,477606,482934,487911,492661,497071,501151,505051,508561,511756,514789,517593,520142,522536,524731,526709,528531,530107,531556,532876,534131,535180,536158,536954,537704,538376,538992,539536};

struct CGroup{
	int ni;
	int ma;
	int hi;
	int pe;
};
CGroup g[101];

struct UV { int u,v; };
UV uv[5555];
long m;

int oldness(long j,long t){
	return t-g[j].pe/g[j].ni;
}

int add(long j,long p,long s,long t){
	assert(g[j].ni>0);
	assert(g[j].ni<4);
	if(0){
		return 0;
	}
	uv[m].u=g[j].hi;
	uv[m].v=p;
	++m;
	if(g[j].ni==3){
		g[j].ni=0;
	}else{
		if(s<j){
			assert(g[s].ni==0);
			g[s]=g[j];
			g[j].ni=0;
			j=s;
		}
		if(s>g[j].ma){
			g[j].ma=s;
		}
		g[j].ni+=1;
		g[j].pe+=t;
	}
	return 1;
}

double calcdd(double d,double h){
	return pow(d,1.5)*pow(h/N,0.5);
}

main(){
	{
		long t;
		scanf("%ld",&t);
		assert(t==T);
	}
	{
		long r;
		scanf("%ld",&r);
		assert(r==4);
	}
	double fq=double(N)/double(T);
	long p=0;
	for(long t=0;t<T;++t){
		m=0;
		long n=-1;
		scanf("%ld",&n);
		assert(n>=0);
		assert(n<=5400);
		fq=(fq*39+n)/40;
		for(long i=0;i<n;++i){
			++p;
			long s=-1;
			scanf("%ld",&s);
			assert(s>=0);
			assert(s<=100);

			double best_dd=25/(fq/(double(N)/double(T)));
			long best_j=-1;
			long incl_j=-1;
			for(long j=0;j<=100;++j){
				if(g[j].ni){
					if(oldness(j,t)>150){
						g[j].ni=0;
					}else{
						long d,h;
						if(s<j){
							d=g[j].ma-s;
							h=di[g[j].ma]-di[s];
						}else if(s>g[j].ma){
							d=s-j;
							h=di[s]-di[j];
						}else{
							d=g[j].ma-j;
							h=di[g[j].ma]-di[j];
							assert(incl_j<0);
							incl_j=j;
						}
						double dd=calcdd(d,h)-calcdd(g[j].ma-j,di[g[j].ma]-di[j]);
						dd*=pow(double(g[j].ni),0.9)+0.30;
						if(dd<best_dd){
							best_dd=dd;
							best_j=j;
						}
					}
				}
			}
			if(incl_j>=0&&incl_j!=best_j){
				g[incl_j].ni=0;
			}
			if(best_j>=0){
				if(add(best_j,p,s,t)){
					goto hoge;
				}
			}
			if(incl_j>=0){
				g[incl_j].ni=0;
			}
			{
				assert(g[s].ni==0);
				g[s].ni=1;
				g[s].hi=p;
				g[s].ma=s;
				g[s].pe=t;
			}
			hoge:;
		}
		printf("%d\n",m);
		for(long k=0;k<m;++k){
			printf("%d %d\n",uv[k].u,uv[k].v);
		}
		fflush(stdout);
	}
}