#include <bits/stdc++.h>

using namespace std;

#define INF ((1LL<<31)-1)
#define D 16

struct SegTree {
	int segSize, realSegSize, nodeSize;
	vector<int> seg;

	void init(int n) {
		realSegSize = n;

		nodeSize = 0;
		for (segSize = 1; segSize < n; segSize *= D) nodeSize += segSize;

		seg = vector<int>(nodeSize+n, INF);
	}

	int get(int n) {
		if (n < (int)seg.size()) return seg[n];
		else return INF;
	}
	void set(int n, int v) {
		if (n < (int)seg.size()) seg[n] = v;
	}

	void update(int pos, int val) {
		int n = nodeSize + pos;
		set(n, val);
		while (n) {
			n = (n-1)/D;

			int r = INF;
			for (int i = 0; i < D; ++i) {
				r = min(r, seg[n*D+i+1]);
			}
			set(n, r);
		}
	}
	int get(int n, int l, int r, int L, int R) {
//		cout << n << " " << l << " " << r << endl;
		if (L <= l && r <= R) return get(n);
		else if (R <= l || r <= L) return INF;
		else {
			int ret = INF;
			int prev = l;
			for (int i = 0; i < D; ++i) {
				int next = i == D-1 ? r : prev + (r-l)/D;
				ret = min(ret, get(n*D+i+1, prev, next, L, R));
				prev = next;
			}
			return ret;
		}
	}
	int get(int L, int R) {
		return get(0, 0, segSize, L, R);
	}
};

struct Query {
	int y1, x1, y2, x2;
};

int main() {
	int H, W, Q;
	while ( cin >> H >> W >> Q, H || W || Q ) {
		vector< vector<int> > m(H, vector<int>(W, 0));

		for (int y = 0; y < H; ++y) {
			for (int x = 0; x < W; ++x) {
				cin >> m[y][x];
			}
		}

		bool isSegRow = H < W;
		vector<SegTree> seg;

		if (isSegRow) {
			seg.resize(H);
			for (int y = 0; y < H; ++y) {
				seg[y].init(W);
			}
		}
		else {
			seg.resize(W);
			for (int x = 0; x < W; ++x) {
				seg[x].init(H);
			}
		}

		for (int y = 0; y < H; ++y) {
			for (int x = 0; x < W; ++x) {
				if (isSegRow) seg[y].update(x, m[y][x]);
				else seg[x].update(y, m[y][x]);
			}
		}

		for (int t = 0; t < Q; ++t) {
			int y1, x1, y2, x2; cin >> y1 >> x1 >> y2 >> x2;

			int ans = INF;
			if (isSegRow) {
				for (int y = y1; y <= y2; ++y) {
					ans = min(ans, seg[y].get(x1, x2+1));
				}
			}
			else {
				for (int x = x1; x <= x2; ++x) {
					ans = min(ans, seg[x].get(y1, y2+1));
				}
			}
			cout << ans << endl;
		}
	}
}