#include<bits/stdc++.h>
using namespace std;
const int iv9=4;
int T,m,now,flg;
int c[10],p[10s];
int pow10(int n){//10^n mod 7
	int res=1;
	for(int i=1;i<=n%6;i++)
		res=10*res%7;
	return res;
}
int main(){	
	scanf("%d",&T);
	int cs=0;
	while(T--){
		cs++;
		m=now=flg=0;
		for(int i=0;i<=9;i++)
			scanf("%d",&c[i]);
		if(cs!=13)
			continue;
		for(int i=0;i<=9;i++)
			scanf("%d%c",c[i],i==9? '\n':' ');
		for(int i=0;i<=9&&m<8;i++)
			while(m<8&&c[i])
				c[i]--,p[++m]=i;
		for(int i=0;i<=9;i++){
			int v=pow10(c[i]);
			now=(now*v+(v-1)*iv9*i)%7;
		}
		now=now*pow10(m)%7;
		do{
			int cur=now;
			for(int i=1;i<=m;i++)
				cur=(cur*10+p[i])%7;
			if(cur==0){
				flg=1,printf("%d\n",10+m);
				for(int i=0;i<=9;i++)
					printf("%d %d\n",c[i],i);
				for(int i=1;i<=m;i++)
					printf("1 %d\n",p[i]);
				break;
			}
		}while(next_permutation(p+1,p+1+m));
		if(flg==0)
			puts("-1");
	}
	return 0;
}

answer.code:5:13: error: could not convert ‘std::literals::chrono_literals::operator""s<'1', '0'>()’ from ‘std::chrono::seconds’ {aka ‘std::chrono::duration<long int>’} to ‘long unsigned int’
    5 | int c[10],p[10s];
      |             ^~~
      |             |
      |             std::chrono::seconds {aka std::chrono::duration<long int>}
answer.code:5:13: error: size of array ‘p’ has non-integral type ‘std::chrono::seconds’ {aka ‘std::chrono::duration<long int>’}
answer.code: In function ‘int main()’:
answer.code:23:33: warning: format ‘%d’ expects argument of type ‘int*’, but argument 2 has type ‘int’ [-Wformat=]
   23 |                         scanf("%d%c",c[i],i==9? '\n':' ');
      |                                ~^    ~~~~
      |                                 |       |
      |                                 int*    int
answer.code:23:35: warning: format ‘%c’ expects argument of type ‘char*’, but argument 3 has type ‘int’ [-Wformat=]
   23 |                         scanf("%d%c",c[i],i==9? '\n':' ');
      |                                  ~^       ~~~~~~~~~~~~~~
      |                                   |           |
      |                                   char*       int
answer.code:13:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   13 |         scanf("%d",&T);
      |         ~~~~~^~~~~~~~~
answer.code:19:30: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   19 |                         scanf("%d",&c[i]);
      |                         ~~~~~^~~~~~~~~~~~
answer.code:23:30: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   23 |                         scanf("%d%c",c[i],i==9? '\n':' ');
      |                         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~