#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vector<int>> vvi;
#define pb push_back
#define eb emplace_back
#define ppb pop_back
#define ppf pop_front
#define pf push_front
#define bk back()
#define frnt front()
#define ins insert
#define er erase
#define sc second
#define fr first
#define mp make_pair
#define mt make_tuple
#define lb lower_bound
#define ub upper_bound
#define REP(i,n) for (int i = 0; i < n; ++i)
#define REP1(i,n) for (int i = 1; i <= n; ++i)
#define REPV(i,n) for (int i = n-1; i >= 0; --i)
#define REPV1(i, n) for (int i = n; i > 0; --i)
#define ALL(a) a.begin(), a.end()
#define SORT(a) sort(ALL(a))
#define MNTO(x,y) x = min(x, (__typeof__(x))y)
#define MXTO(x,y) x = max(x, (__typeof__(x))y)
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n, m;
cin >> n >> m;
vector<vi> s(n, vi(m));
REP(i, n) {
REP(j, m) cin >> s[i][j];
}
int totbanana = 0;
REP(i, n) {
REP(j, m) {
totbanana += s[i][j];
}
}
int ans = INT_MAX;
vector<int> a(m);
REP(r1, n) {
fill(ALL(a), 0);
for (int r2 = r1; r2 < n; ++r2) {
REP(c, m) a[c] += s[r2][c];
int height = r2-r1+1;
int bh = 0, bo = INT_MIN;
REP(c, m) {
int x = 2*a[c]-height;
bh = max(x, bh+x);
MXTO(bo, bh);
}
MNTO(ans, totbanana-bo);
}
}
cout << ans;
return 0;
}
