#include <bits/stdc++.h>
using namespace std;
#define InTheNameOfGod ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
using ll = long long;

const int maxN = 2e5 + 5;
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;

vector<int> p, s, mo;
vector<set<int> > edges;
int curr;

int root(int x) {
   if(p[x] == x) return x;
   if(p[x] == -1) return -1;

   return (p[x] = root(p[x]));
}

void connect(int a, int b) {
   a = root(a), b = root(b);

   if(a == b || a == -1 || b == -1) return;

   if(s[a] < s[b]) swap(a, b);

   p[b] = a;
   s[a] += s[b];
   for(int i : edges[b]) {
      if(edges[a].find(i) == edges[a].end()) edges[a].insert(i);
      else {
         mo[i] = curr;
         edges[a].erase(i);
      }
   }
}

int main() {
   InTheNameOfGod;

   int n,m,q;
   cin >> n >> m >> q;
   vector<pair<int, int> > ma;
   for(int i = 0; i < n*m; i++) {
      int x;
      cin >> x;
      ma.push_back({x, i});
   }

   p.resize(n*m+1, -1);
   s.resize(n*m+1, 0);
   edges.resize(n*m+1);
   mo.resize(q, -1);

   sort(ma.begin(), ma.end());

   for(int i = 0; i < q; i++) {
      int a,b,c,d;
      cin >> a >> b >> c >> d;
      edges[m*(a-1) + b-1].insert(i);
      edges[m*(c-1) + d-1].insert(i);
   }
   
   for(auto i : ma) {
      curr = i.first;
      int x = i.second;
      p[x] = x;
      s[x] = 1;
      if(x % m > 0) connect(x, x-1);
      if(x % m < m-1) connect(x, x+1);
      if(x > m-1) connect(x, x-m);
      if(x < (n-1)*m) connect(x, x+m);
   }

   for(int i : mo) cout << i << "\n";
   
   return 0;
}