#include <bits/stdc++.h>
using namespace std;
inline void setmin(int &x, int y) {
  if (y < x) x = y;
}
inline void setmax(int &x, int y) {
  if (y > x) x = y;
}
inline void setmin(long long &x, long long y) {
  if (y < x) x = y;
}
inline void setmax(long long &x, long long y) {
  if (y > x) x = y;
}
const int N = 100000;
const int inf = (int)1e9 + 1;
const long long big = (long long)1e18 + 1;
const int P = 239;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const double eps = 1e-9;
const double pi = atan2(0, -1);
const int ABC = 26;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.precision(20);
  cout << fixed;
  int n, m, k;
  cin >> n >> m >> k;
  int a[n][m];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) cin >> a[i][j];
  if (n <= k) {
    int ans = inf;
    for (int mask = 0; mask < (1 << n); mask++) {
      int cnt = 0;
      for (int j = 0; j < m; j++) {
        int c0 = 0, c1 = 0;
        for (int i = 0; i < n; i++)
          if (a[i][j] == ((mask >> i) & 1))
            c0++;
          else
            c1++;
        cnt += min(c0, c1);
      }
      setmin(ans, cnt);
    }
    cout << (ans <= k ? ans : -1) << "\n";
  } else {
    int ans = inf;
    for (int s = 0; s < n; s++) {
      int cnt = 0;
      for (int i = 0; i < n; i++) {
        int c0 = 0, c1 = 0;
        for (int j = 0; j < m; j++)
          if (a[i][j] == a[s][j])
            c0++;
          else
            c1++;
        cnt += min(c0, c1);
      }
      setmin(ans, cnt);
    }
    cout << (ans <= k ? ans : -1) << "\n";
  }
  return 0;
}
