#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
#include <iostream>
using namespace std;
int N, Q, L, R;
int input[100005];
int segTree[400020];
int max_num = 0x7FFFFFFF;
int i, j, lo, hi;
int fake_n;
int ql, qh;
int nl, nh;
int Level;
void construct_tree_min(int input[], int segTree[], int low, int high, int pos) {
if (low == high)
{
segTree[pos] = input[low];
return;
}
int mid = (low + high) / 2;
construct_tree_min(input, segTree, low, mid, 2 * pos + 1);
construct_tree_min(input, segTree, mid + 1, high, 2 * pos + 2);
segTree[pos] = min(segTree[2 * pos + 1], segTree[2 * pos + 2]);
}
void rangeQuery(int segTree[], int value, int low, int high, int level, int pos ) {
//printf("low %d high %d value %d\n", low, high, segTree[pos] );
if (segTree[pos] == value && level == Level) // overlap
{
//printf("call %d %d\n",low,high);
ql = low;
qh = high;
return;
}
if (high == low) // no overlap
{
return;
}
int mid = (low + high) / 2;
rangeQuery(segTree, value, low, mid, level +1, 2 * pos + 1 );
rangeQuery(segTree, value, mid + 1, high,level +1 , 2 * pos + 2);
}
void fake_nf()
{
fake_n = 1;
while (N > fake_n)
{
fake_n *= 2;
}
}
void print_segTree()
{
for (int i = 0; i < fake_n * 2 -1; i++)
{
printf("%d ", segTree[i]);
}
printf("\n");
}
int main()
{
//ip1 N Q
scanf(" %d %d", &N, &Q);
fake_nf();
//ip2
for (int i = 1; i <= N; i++)
{
scanf(" %d", &input[i]);
}
//ip_fake
for (int i = N + 1; i <= fake_n; i++)
input[i] = max_num;
//Makig tree
construct_tree_min(input, segTree, 1, fake_n, 0);
//print tree
//print_segTree();
//Query
for (int i = 0; i < Q; i++)
{
int time;
scanf(" %d", &time);
Level = time;
for (int i = 0; i < time; i++)
{
int a;
scanf(" %d", &a);
rangeQuery( segTree, a, 1, fake_n, 0 , 0 );
if (i == 0)
{
//printf("1\n");
nl = ql;
nh = qh;
}
else
{
if (qh + 1 == nl)
{
//printf("2\n");
nl = ql;
}
else if (nh + 1 == ql)
{
//printf("3 nh %d ql %d\n",nh,ql);
nh = qh;
}
else
{
printf("-1\n");
break;
}
}
if (i == time - 1)
{
if (nh > N)
nh = N;
printf("%d %d\n", nl, nh);
}
}
}
return 0;
}
