#include <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>
#include <functional>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = { -1, 0, 1, 0 }; const int dy[] = { 0, 1, 0, -1 };

char ans_c(int c){
	if (c < 10)
		return '0'+c;
	return 'A' + c - 10;
}

int main() {
	int N, M, Q;
	while (cin >> N >> M >> Q, N){
		string switch_s;
		string bswitch_s;
		string light_s;
		string blight_s;
		vector<vector<bool>> vvb(M,vector<bool>(N,true));
		REP(i, N)
			bswitch_s.append(i,'0');
		REP(i, M)
			blight_s.append(i,'0');

		REP(i, Q){
			cin >> switch_s;
			cin >> light_s;
			//-----------//
			REP(j, N){
				REP(k, M){
					if ((switch_s[j]=='0') != (light_s[k] == blight_s[k])){
						vvb[k][j]=false;
					}
				}
			}
			//-----------//
			bswitch_s= switch_s;
			blight_s = light_s;
		}


		REP(i,M){
			int count = 0;
			int ans = 0;
			REP(j, N){
				if (vvb[i][j]){
					count++;
					ans = j;
				}
			}
			if (count == 1)cout << ans_c(ans);
			else cout << '?';
		}
		cout << endl;
	}
}