#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstdlib>

#include<cstring>

#include<string>

#include<cmath>

#include<map>

#include<set>

#include<vector>

#include<queue>

#include<bitset>

#include<ctime>

#include<deque>

#include<stack>

#include<functional>

#include<sstream>

//#include<cctype>

//#pragma GCC optimize(2)

using namespace std;

#define maxn 200005

#define inf 0x7fffffff

//#define INF 1e18

#define rdint(x) scanf("%d",&x)

#define rdllt(x) scanf("%lld",&x)

#define rdult(x) scanf("%lu",&x)

#define rdlf(x) scanf("%lf",&x)

#define rdstr(x) scanf("%s",x)

typedef long long  ll;

typedef unsigned long long ull;

typedef unsigned int U;

#define ms(x) memset((x),0,sizeof(x))

const long long int mod = 1e9;

#define Mod 1000000000

#define sq(x) (x)*(x)

#define eps 1e-5

typedef pair<int, int> pii;

#define pi acos(-1.0)

//const int N = 1005;

#define REP(i,n) for(int i=0;i<(n);i++)

typedef pair<int, int> pii;

inline int rd() {

	int x = 0;

	char c = getchar();

	bool f = false;

	while (!isdigit(c)) {

		if (c == '-') f = true;

		c = getchar();

	}

	while (isdigit(c)) {

		x = (x << 1) + (x << 3) + (c ^ 48);

		c = getchar();

	}

	return f ? -x : x;

}

ll gcd(ll a, ll b) {

	return b == 0 ? a : gcd(b, a%b);

}

int sqr(int x) { return x * x; }

/*ll ans;

ll exgcd(ll a, ll b, ll &x, ll &y) {

	if (!b) {

		x = 1; y = 0; return a;

	}

	ans = exgcd(b, a%b, x, y);

	ll t = x; x = y; y = t - a / b * y;

	return ans;

}

*/

int n, m, K;

int a[200][200];

bool fg;

int pre[maxn];

int dp[maxn];

int minn = inf;

void sol() {

	for (int i = 1; i <= n; i++) {

		ms(dp);

		for (int j = i; j <= n; j++) {

			ms(pre);

			for (int k = 1; k <= m; k++)

				dp[k] += a[j][k];

			for (int k = 1; k <= m; k++)pre[k] = pre[k - 1] + dp[k];

			int l = 1, r = 1;

			while (1) {

				if (r > m)break;

				while (pre[r] - pre[l - 1] < K&&r <= m)r++;

				if (pre[r] - pre[l - 1] >= K&&r<=m) {

					minn = min(minn, (j - i + 1)*(r - l + 1));

					fg = 1;

				}

				while (pre[r] - pre[l - 1] >= K && l <= r) {

					minn = min(minn, (r - l + 1)*(j - i + 1));

					l++;

					fg = 1;

				}

			}

		}

	}

}

int main()

{

	//ios::sync_with_stdio(0);

	rdint(n); rdint(m); rdint(K);

	for (int i = 1; i <= n; i++) {

		for (int j = 1; j <= m; j++)rdint(a[i][j]);

	}

	sol();

	if (fg == 0)cout << -1 << endl;

	else {

		cout << minn << endl;

	}

	return 0;

}