#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, U b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, U b) {
  if (a < b) a = b;
}
template <typename T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T, class T1>
inline void gn(T &first, T1 &second) {
  gn(first);
  gn(second);
}
template <class T, class T1, class T2>
inline void gn(T &first, T1 &second, T2 &z) {
  gn(first);
  gn(second);
  gn(z);
}
template <typename T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <typename T>
inline void println(T first) {
  print(first), putchar('\n');
}
template <typename T>
inline void printsp(T first) {
  print(first), putchar(' ');
}
template <class T, class T1>
inline void print(T first, T1 second) {
  printsp(first), println(second);
}
template <class T, class T1, class T2>
inline void print(T first, T1 second, T2 z) {
  printsp(first), printsp(second), println(z);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
int a[111][111];
int b[111];
int dp[111][1 << 10];
int main() {
  int n, m, k;
  gn(n, m, k);
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) gn(a[i][j]);
  if (m <= k) {
    for (int i = 0; i < n; i++) {
      b[i] = 0;
      for (int j = 0; j < m; j++) {
        b[i] <<= 1;
        b[i] += a[i][j];
      }
    }
    for (int i = 1; i <= n; i++)
      for (int j = 0; j < 1 << m; j++) dp[i][j] = 0x3f3f3f3f;
    int all = (1 << m) - 1;
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < 1 << m; j++) {
        smin(dp[i + 1][j], dp[i][j] + (__builtin_popcount(b[i] ^ j)));
        smin(dp[i + 1][all ^ j],
             dp[i][j] + (__builtin_popcount(b[i] ^ all ^ j)));
      }
    }
    int ans = 0x3f3f3f3f;
    for (int i = 0; i < 1 << m; i++) smin(ans, dp[n][i]);
    if (ans <= k)
      println(ans);
    else
      puts("-1");
  } else {
    int ans = 0x3f3f3f3f;
    for (int i = 0; i < m; i++) {
      int tot = 0;
      for (int j = 0; j < m; j++) {
        int c1 = 0, c2 = 0;
        for (int k = 0; k < n; k++) {
          if (a[k][i] != a[k][j])
            c1++;
          else
            c2++;
        }
        tot += min(c1, c2);
      }
      smin(ans, tot);
    }
    if (ans <= k)
      println(ans);
    else
      puts("-1");
  }
  return 0;
}
