2 3
1 2 1 3
1 2 1 3 2 3
 3 7
8 2 7 9 8 1
3 1 8 1 2 7 4 7 4 2 1 4 4 6
 1 10
3 9
3 2 3 4 5 3 5 7 8 6 2 5 7 8 2 4 1 7 5 1
 12 1
6 2 6 4 8 6 6 9 5 6 6 1 9 1 1 3 3 9 2 4 5 2 8 1
6 7
 2 3
1 2 7 8
1 3 2 4 7 9
 3 2
1 2 1 3 2 3
1 2 4 5
 3 8
8 9 8 5 9 2
8 4 8 3 2 6 4 2 4 3 3 7 3 6 1 6
 8 5
7 9 6 7 4 7 2 1 4 9 2 9 4 2 9 6
8 7 1 8 8 5 3 5 3 8
 4 4
1 2 1 3 6 7 6 8
1 4 1 5 6 1 6 9
 3 10
6 1 4 1 4 6
7 1 8 1 8 5 3 2 9 7 9 3 5 9 5 3 5 7 7 2
 3 3
1 2 1 3 2 3
1 2 1 3 2 3
 11 1
2 6 1 4 7 9 7 6 8 1 4 8 4 7 7 2 1 7 9 6 6 5
3 1
 5 6
1 7 5 6 6 9 3 6 1 9
2 7 2 5 8 5 4 8 4 2 8 2
 8 1
1 6 7 6 7 3 9 2 1 2 8 6 2 3 4 1
8 3
 9 4
2 8 8 9 8 1 9 2 5 9 3 5 3 2 5 2 9 1
8 4 8 7 6 8 4 7
 4 7
9 2 4 1 2 3 2 7
6 1 5 4 7 5 6 3 1 5 8 1 1 4
 3 3
1 2 5 6 7 8
2 3 4 5 8 9
 1 7
8 4
9 8 8 2 6 8 8 1 7 8 2 1 9 5
 2 2
1 2 2 3
2 3 3 4
 12 12
6 7 5 4 7 8 2 9 8 5 3 5 1 6 7 3 7 9 5 7 1 8 6 8
6 4 2 1 7 8 1 6 8 5 9 8 1 5 7 2 5 9 6 3 9 2 9 4
 9 1
3 4 3 2 3 7 3 5 9 4 1 9 6 4 5 2 7 6
8 3
 9 2
9 6 1 6 2 5 7 3 8 1 7 2 9 1 2 8 3 8
6 4 4 5
 3 9
9 7 9 2 7 2
9 8 1 9 3 9 6 3 8 6 4 6 1 3 5 4 5 3
 3 6
3 5 7 4 7 5
3 9 3 2 8 6 6 2 8 2 6 9
 2 1
1 2 1 3
1 2
 9 1
1 8 7 6 7 2 7 9 4 1 4 3 3 8 4 6 9 6
9 4
 2 2
1 2 2 4
1 2 1 3
 6 9
8 1 8 4 2 8 2 1 4 1 4 2
8 3 8 6 7 8 5 8 6 7 5 7 9 6 5 6 5 3
 12 2
3 1 8 2 6 9 2 6 5 4 4 3 4 1 4 2 6 3 9 7 9 4 3 2
7 1 4 1
 2 1
4 5 6 7
4 7
 4 3
1 2 4 5 6 7 8 9
1 2 8 9 3 1
 12 12
7 6 3 8 8 4 4 7 1 9 9 5 7 5 4 9 8 6 2 7 7 3 3 6
9 1 2 4 9 8 5 3 6 7 3 8 2 7 5 9 6 4 3 1 2 6 1 4
 12 5
9 2 6 7 7 8 3 4 8 4 7 1 2 1 7 3 7 2 5 6 3 8 1 5
3 7 7 5 7 4 5 8 4 6
 7 6
6 2 9 2 6 5 2 4 1 2 4 5 6 7
3 9 5 1 9 8 9 5 3 4 2 3
 6 4
2 7 3 2 8 3 1 5 7 4 3 5
2 6 9 8 8 6 6 9
 10 2
4 9 2 1 5 1 6 2 6 7 2 7 5 8 1 7 5 3 9 1
9 7 1 4
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1 2 2 3 1 3 4 5
1 3 3 2 1 2 4 6
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2 1 8 9 3 1
1 2 4 5 6 7 8 9
 1 12
6 8
8 4 8 2 5 8 9 8 8 3 8 7 8 1 1 3 1 9 4 3 7 3 5 7
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1 2 3 4 5 6 7 8
2 3 4 5 6 7 8 1
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1 5 7 1 2 1
9 5 5 6 3 5 4 7 8 3 9 6 8 4 9 8 4 6 3 4
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1 2 4 5 6 7
4 7 1 3
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4 7 7 3 4 3 9 4 3 9
7 5 7 8 1 7 7 2 6 2 1 2
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2 6 6 7 6 4 6 1 9 6 7 4 1 9
6 5 3 6 6 8
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2 7 2 5
7 1 9 7 8 9 4 9 8 1 3 9 3 8
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1 2 1 3
1 2 1 3
 2 11
6 1 3 6
1 7 1 2 1 5 1 4 5 3 3 2 9 8 4 2 7 5 4 9 2 9
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1 6 2 6 8 3 6 4 4 8 7 2 7 5 9 4 2 4 9 5 8 5 3 6
2 8 6 9 2 6 7 4 6 5 6 3 5 8 7 8 7 1 1 9 9 7 7 3
 4 12
2 8 3 1 2 1 9 4
9 5 5 3 1 6 3 7 7 1 8 5 6 5 4 6 1 9 1 4 2 5 9 8

-1 -1 3 6 -1 -1 0 0 -1 1 -1 1 0 -1 8 -1 0 8 0 -1 3 0 9 3 1 -1 0 8 -1 -1 1 -1 -1 -1 0 -1 -1 1 8 -1 0 -1 7 6 7 1 0 -1 -1
/// Code by Leonardo16
#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")
/// Macros
#define int long long
#define ll long long
#define sz size
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define ii pair<int,int>
#define vii vector<ii>
#define fst first
#define scd second
#define pb push_back
#define fl '\n'
#define el endl
#define all(x) x.begin() , x.end()
#define rall(x) x.rbegin() , x.rend()
/// Functions
#define db(x) cerr << #x << ": " << (x) << '\n';
#define random() __builtin_ia32_rdtsc()
#define lg2(x) 31-__builtin_clz(x)
#define lg2ll(x) 63-__builtin_clzll(x)
#define pi acos(-1)
#define YN(x) cout<<((x)?("YES"):("NO"))<<fl;
#define yn(x) cout<<((x)?("Yes"):("No"))<<fl;
/// Red-Black Tree Template
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//typedef tree < long long ,  null_type ,  less<long long> ,  rb_tree_tag ,  tree_order_statistics_node_update > ordered_set;
//#define less_than(n) order_of_key(n)
//#define en_pos(n) find_by_order(n)
/// Prime numbers  173,179,311,331,737,1009,2011,2027,3079,4001,100003
///===================================================================
int n,m;
vi v1,v2;
int og[22];

main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    int n,m;
    cin>>n>>m;

    for(int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;
        int a=0;
        a+=(1<<x);
        a+=(1<<y);
        v1.pb(a);
    }

    for(int i=0;i<m;i++){
        int x,y;
        cin>>x>>y;
        int a=0;
        a+=(1<<x);
        a+=(1<<y);
        v2.pb(a);
    }

    bool can=true;
    int uni=0;

    for(int i=0;i<n;i++){
        int cnt=0;

        for(int j=0;j<m;j++){
            if( (v1[i]&v2[j])!=0 && __builtin_popcountll((v1[i]&v2[j]))==1  ){
                cout<<i<<" "<<j<<fl;
                og[j]++;
                cnt++;
                uni++;
                if(og[j]>1){
                    can=false;
                }
            }
        }

        if(cnt>1){
            can=false;
        }

    }

    if(can==false||uni==0){
        cout<<-1;
        return 0;
    }

    if(uni==1){
        cout<<1;
    }else{
        cout<<0;
    }


return 0;}



