#include <bits/stdc++.h>
namespace chtholly {
inline int read() {
  int x = 0, f = 1;
  char c = getchar();
  for (; !isdigit(c); c = getchar()) f ^= c == '-';
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return f ? x : -x;
}
template <typename mitsuha>
inline bool read(mitsuha &x) {
  x = 0;
  int f = 1;
  char c = getchar();
  for (; !isdigit(c) && ~c; c = getchar()) f ^= c == '-';
  if (!~c) return 0;
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return x = f ? x : -x, 1;
}
template <typename mitsuha>
inline int write(mitsuha x) {
  if (!x) return 0 & putchar(48);
  if (x < 0) x = -x, putchar('-');
  int bit[20], i, p = 0;
  for (; x; x /= 10) bit[++p] = x % 10;
  for (i = p; i; --i) putchar(bit[i] + 48);
  return 0;
}
inline char fuhao() {
  char c = getchar();
  for (; isspace(c); c = getchar())
    ;
  return c;
}
}  // namespace chtholly
using namespace chtholly;
using namespace std;
const int yuzu = 1e4, _ = 105, inf = yuzu * _;
typedef int fuko[yuzu | 10];
char c[yuzu | 10];
set<int> s[_];
int n, m;
int suan(int r, int c) {
  int ans;
  auto p = s[r].lower_bound(c);
  if (p == s[r].end()) {
    ans = min(min(min(abs(*s[r].rbegin() - c), abs(*s[r].rbegin() + m - c)),
                  abs(c + m - *s[r].rbegin())),
              min(min(abs(*s[r].begin() - c), abs(*s[r].begin() + m - c)),
                  abs(c + m - *s[r].begin())));
  } else if (p == s[r].begin()) {
    ans = min(min(min(abs(*p - c), abs(*p + m - c)), abs(c + m - *p)),
              min(min(abs(*s[r].rbegin() - c), abs(*s[r].rbegin() + m - c)),
                  abs(c + m - *s[r].rbegin())));
  } else {
    ans = min(min(min(abs(*p - c), abs(*p + m - c)), abs(c + m - *p)),
              min(min(abs(c - *--s[r].lower_bound(c)),
                      abs(c + m - *--s[r].lower_bound(c))),
                  abs(*--s[r].lower_bound(c) + m - c)));
  }
  return ans;
}
int main() {
  int i, j, ans = inf;
  scanf("%d%d", &n, &m);
  for (i = 1; i <= n; ++i) {
    scanf("%s", c + 1);
    for (j = 1; j <= m; ++j)
      if (c[j] & 1) s[i].insert(j);
  }
  for (j = 1; j <= m; ++j) {
    int tmp = 0;
    for (i = 1; i <= n; ++i) {
      if (s[i].empty()) return puts("-1"), 0;
      tmp += suan(i, j);
    }
    ans = min(ans, tmp);
  }
  write(ans);
}
