#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);++i)
#define FOR(i,n,j) for(int i=(j);i<(n);++i)
#define ssort(n) sort((n).begin(),(n).end())
#define rsort(n) sort((n).begin(),(n).end(),greater<int>())
using ll=long long;
using ld=long double;
typedef pair<int,int> P;
typedef pair<P,int> COST;
#define repl(i,n) for(ll i=0;i<(n);++i)
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
using Graf_char=vector<vector<char>>;
using Graf_int=vector<vector<int>>;
#define MAX 100000

int main()
{
    int n,m;
    cin >> n >> m;
    vector<int> s(m),c(m);
    rep(i,m){
        cin >> s[i] >> c[i];
    }
    vector<int> num(n,-1);
    rep(i,m){
        if(num[s[i]-1]!=-1){
            if(num[s[i]-1]!=c[i]){
                cout << -1 << endl;
                return 0;
            }
        }
        else{
            num[s[i]-1]=c[i];
            if(s[i]-1==0&&c[i]==0&&n>1){
                cout << -1 << endl;
                return 0;
            }
        }
    }
    rep(i,n){
        if(n>1&&i==0&&num[i]==-1){
            cout << 1;
        }else if(num[i]==-1){
            cout << 0;
        }else{
            cout << num[i];
        }
    }
    cout << endl;
}
#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep0(n) for (int counter = 0; counter < (int)(n); counter++)
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = s; i < (int)(n); i++)
#define rep3(i, s, n) for (int i = s; i > (int)(n); i--)
#define ALL(obj) obj.begin(), obj.end()
#define from1(obj) obj.begin() + 1, obj.end()
#define db(x) cerr << #x << ":" << (x) << " "
#define dbl(x) cerr << #x << ":" << (x) << "\n"
#define db2(x, y) cerr << #x << ":" << (x) << ", " << #y << ":" << (y) << " "
#define db2l(x, y) cerr << #x << ":" << (x) << ", " << #y << ":" << (y) << "\n"
#define dbl2(x, y) cerr << #x << ":" << (x) << "\n" << #y << ":" << (y) << "\n"
#define db3(x, y, z) cerr << #x << ":" << (x) << ", " << #y << ":" << (y) << " " << #z << ":" << (z) << " "
#define db3l(x, y, z) cerr << #x << ":" << (x) << ", " << #y << ":" << (y) << ", " << #z << ":" << (z) << "\n"
#define dbl3(x, y, z) cerr << #x << ":" << (x) << "\n" << #y << ":" << (y) << "\n" << #z << ":" << (z) << "\n"
#define dbp(p) cerr << #p << ":(" << p.first << ", " << p.second << ") "
#define dbpl(p) cerr << #p << ":(" << p.first << ", " << p.second << ")\n"
#define dbt3(t3) cerr << #t3 << ":(" << get<0>(t3) << ", " << get<1>(t3) << ", " << get<2>(t3) << ") "
#define dbt3l(t3) cerr << #t3 << ":(" << get<0>(t3) << ", " << get<1>(t3) << ", " << get<2>(t3) << ")\n"
#define dbt4(t4) cerr << #t4 << ":(" << get<0>(t4) << ", " << get<1>(t4) << ", " << get<2>(t4) << ", " << get<3>(t4) << ") "
#define dbt4l(t4) cerr << #t4 << ":(" << get<0>(t4) << ", " << get<1>(t4) << ", " << get<2>(t4) << ", " << get<3>(t4) << ")\n"
#define dbv(vec) cerr << #vec << ":{ "; for (auto e : vec) cerr << e << ", "; cerr << "}\n"
#define dbvp(vec) cerr << #vec << ":{ "; for (auto p : vec) cerr << "(" << p.first << ", " << p.second << "), "; cerr << "}\n"
#define dbvv(vv) cerr << #vv << ":{\n"; for (auto vec : vv) { cerr << "{ "; for (auto e : vec) cerr << e << ", "; cerr << "}\n"; } cerr << "}\n"
#define dbm(map) cerr << #map << ":{ "; for (auto p : map) cerr << "(" << p.first << ", " << p.second << "), "; cerr << "}\n"
#define YN(f) cout << (f ? "YES" : "NO") << "\n"
#define Yn(f) cout << (f ? "Yes" : "No") << "\n"
#define yn(f) cout << (f ? "yes" : "no") << "\n"
using ll = long long;
using vi = vector<int>; using vl = vector<ll>; using vs = vector<string>; using vb = vector<bool>;
using vvi = vector<vi>; using vvl = vector<vl>; using vvb = vector<vb>;
using pii = pair<int, int>; using pil = pair<int, ll> ; using pli = pair<ll, int>; using pll = pair<ll, ll>;
using vpii = vector<pii>; using vpll = vector<pll>;
using ti3 = tuple<int, int, int>; using tl3 = tuple<ll, ll, ll>;
using ti4 = tuple<int, int, int, int>; using tl4 = tuple<ll, ll, ll, ll>;
using mii = map<int, int>; using mil = map<int, ll>; using mli = map<ll, int>; using mll = map<ll, ll>;

mii col; // Qの行番号->列番号

bool solve(vi a) {
	for (pii p : col) {
		if (a[p.first] != p.second) return false;
	}
	rep(i, 7) rep2(j, i + 1, 8) if (abs(a[j] - a[i]) == j - i) return false;
	return true;
}

void draw(vi a) {
	rep(i, 8) {
		rep0(a[i]) cout << '.';
		cout << 'Q';
		rep0(7 - a[i]) cout << '.';
		cout << endl;
	}
}

int main() {
	// 盤面は0-ind
	int k; cin >> k;
	rep0(k) {
		int r, c; cin >> r >> c;
		col[r] = c;
	}	
	vi a(8); rep(i, 8) a[i] = i; // aは {0,1,...,N-1} でなくともよい
	do {
		// aに対応する処理
		if (solve(a)) {
			// dbv(a);
			draw(a);
			break;
		}
	} while (next_permutation(ALL(a)));	
}
