#include <cstdio>
#include <cstring>
using namespace std;
typedef long long ll;

const int N = (1 << 20) + 5;
const ll inf = 1LL << 60;

int n, m, a[N];
ll cnt[N], f[N];

template <typename T>
inline void chkMin(T &x, T y) {
    if (y < x) x = y;
}

void fwt(ll *c, int len) {
    if (len == 1) return;
    int mid = len >> 1;
    fwt(c, mid), fwt(c + mid, mid);
    for (int i = 0; i < mid; i++) {
        ll x = c[i], y = c[i + mid];
        c[i] = x + y, c[i + mid] = x - y;
    }
}

void ifwt(ll *c, int len) {
    if (len == 1) return;
    int mid = len >> 1;
    for (int i = 0; i < mid; i++) {
        ll x = c[i], y = c[i + mid];
        c[i] = (x + y) / 2, c[i + mid] = (x - y) / 2;
    }
    ifwt(c, mid), ifwt(c + mid, mid);
}

int main() {
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i++) {
        char s[N];
        scanf("%s", s + 1);
        for (int j = 1; j <= m; j++) a[j] |= ((s[j] - '0') << (i - 1));
    }
    for (int i = 1; i <= m; i++) ++cnt[a[i]];
    for (int i = 0; i < (1 << n); i++) f[i] = f[i >> 1] + (i & 1);
    for (int i = 0; i < (1 << n); i++) chkMin(f[i], n - f[i]);
    
    fwt(cnt, (1 << n)), fwt(f, (1 << n));
    for (int i = 0; i < (1 << n); i++) f[i] = f[i] * cnt[i];
    ifwt(f, (1 << n));
    
    ll ans = inf;
    for (int i = 0; i < (1 << n); i++) chkMin(ans, f[i]);
    printf("%lld\n", ans);
    
    return 0;
}