ytytu

#pragma comment(linker, "/STACK:16777216")
#include <bits/stdc++.h>
using namespace std;

#define CLR(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define pb push_back
#define SZ(a) ((long)a.size())
#define ALL(a) a.begin(),a.end()
#define FOREACH(i, c) for( __typeof( (c).begin() ) i = (c).begin(); i != (c).end(); ++i )
#define AREA2(x1,y1,x2,y2,x3,y3) ( x1*(y2-y3) + x2*(y3-y1) + x3*(y1-y2) )
#define SQR(x) ((x)*(x))
#define STR string
#define IT iterator
#define ff first
#define ss second
#define MP make_pair
#define EPS 1e-9
#define INF 1000000007

#define chk(a,k) ((bool)(a&(1<<(k))))
#define set0(a,k) (a&(~(1<<(k))))
#define set1(a,k) (a|(1<<(k)))

typedef long long Long;
typedef vector<long> Vl;
typedef vector<Long> VL;
typedef pair<long,long> Pll;
typedef pair<Long,Long> PLL;

inline long FastMax(long x, long y) { return (((y-x)>>(32-1))&(x^y))^y; }
inline long FastMin(long x, long y) { return (((y-x)>>(32-1))&(x^y))^x; }

long IR[] = { 0,-1,0,1,-1,-1,1,1 };
long IC[] = { 1,0,-1,0,1,-1,-1,1 };

#define MAX 10

long N,K;
long cap[MAX+7];
long wei[MAX+7];
long wS[1<<MAX];
bool vi[1<<MAX][MAX+7];
long sol[1<<MAX][MAX+7];
long st[1<<MAX][MAX+7];

long Find( long b, long t ){
    if( !b ) return 0;
    if( vi[b][t] ) return sol[b][t];
    vi[b][t] = true;
    sol[b][t] = INF;
    long subs = b;
    while( 1 ){
        if( wS[subs] <= cap[t] ){
            long tmp = Find( b & ~subs, (t+1)%N );
            if( tmp < sol[b][t] ){
                sol[b][t] = tmp;
                st[b][t] = subs;
            }
        }
        if( !subs ) break;
        subs = (subs-1) & b;
    }
    return sol[b][t] = sol[b][t] + (t==0);
}

void printSol( long b, long t, vector<Pll> &del ){
    long i;//printf("%ld %ld\n",b,t );
    if( (t==0 or !b) and del.size() ){
        printf("%ld",del.size() );
        for( i=0;i<del.size();i++ ){
            printf(" %ld %ld",del[i].ff, del[i].ss );
        }
        printf("\n");
        del.clear();
    }
    if( !b ) return;
    for( i=0;i<K;i++ ){
        if( st[b][t] & (1<<i ) ){
            del.pb( MP( (i+1),( t+1 ) ) );
        }
    }
    printSol( b & ~st[b][t], (t+1)%N, del );
}

int main( void )
{
    long i,j,Icase,k=0;

    //freopen("text1.txt","r",stdin );
    freopen("dhl.in","r",stdin );
    freopen("dhl.out","w",stdout );

    while( cin>>N>>K ){
        long mC = 0;
        for( i=0;i<N;i++ ){
            cin>>cap[i];
            mC = max( mC, cap[i] );
        }
        long mW = 0;
        for( i=0;i<K;i++ ){
            cin>>wei[i];
            mW = max( mW, wei[i] );
        }
        if( mC < mW ){
            printf("-1\n");
            continue;
        }
        for( i=0;i<(1<<K);i++ ){
            wS[i] = 0;
            for( j=0;j<K;j++ ){
                if( i & (1<<j) ){
                    wS[i] += wei[j];
                }
            }
        }
        CLR( vi );
        long ans = Find( (1<<K)-1, 0 );
        printf("%ld\n",ans );
        vector<Pll> del;
        printSol( (1<<K)-1, 0, del );
    }


    return 0;
}