#include <stdio.h>
#include <string.h>
#define N 20
#define M 20
#define N_ ((N + 1) * M + N * (M + 1))
#define INF 0x3f3f3f3f
int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }
int ds[N_], sz[N_]; char cycle[N_];
int find(int i) {
return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}
void join(int i, int j) {
i = find(i);
j = find(j);
if (i == j) {
cycle[i] = 1;
return;
}
if (ds[i] > ds[j])
ds[i] = j, sz[j] += sz[i], cycle[j] |= cycle[i];
else {
if (ds[i] == ds[j])
ds[i]--;
ds[j] = i, sz[i] += sz[j], cycle[i] |= cycle[j];
}
}
int main() {
static char aa[N + 1][M + 1], bb[N][M + 2];
static int nnp[N * M + 2], nnc[N * M + 2], pp[N + M], cc[N * M], dp[N + M + 1][N + M + 1][N * M + 1];
int n, ns, ns2, ns3, np, nc, m, n_, i, j, ks, kp, kc, l, u, v, w, x;
scanf("%d%d", &n, &m), n_ = (n + 1) * m + n * (m + 1);
for (i = 0; i <= n; i++)
scanf("%s", aa[i]);
for (i = 0; i < n; i++)
scanf("%s", bb[i]);
memset(ds, -1, n_ * sizeof *ds);
for (i = 0; i < n_; i++)
sz[i] = 1;
for (i = 0; i < n; i++)
for (j = 0; j < m; j++) {
u = v = -1;
if (aa[i][j] == '0') {
w = i * m + j;
if (u == -1)
u = w;
else
v = w;
}
if (aa[i + 1][j] == '0') {
w = (i + 1) * m + j;
if (u == -1)
u = w;
else
v = w;
}
if (bb[i][j] == '0') {
w = (n + 1) * m + i * (m + 1) + j;
if (u == -1)
u = w;
else
v = w;
}
if (bb[i][j + 1] == '0') {
w = (n + 1) * m + i * (m + 1) + (j + 1);
if (u == -1)
u = w;
else
v = w;
}
if (u != -1 && v != -1)
join(u, v);
}
for (i = 0; i < n_; i++)
if (ds[i] < 0) {
if (!cycle[i])
nnp[sz[i]]++;
else
nnc[sz[i]]++;
}
ns2 = nnp[2], ns3 = nnp[3], ns = ns2 + ns3;
np = 0;
for (l = 4; l <= n * m + 1; l++)
while (nnp[l]--)
pp[np++] = l;
nc = 0;
for (l = 4; l <= n * m + 1; l++)
while (nnc[l]--)
cc[nc++] = l;
for (ks = ns; ks >= 0; ks--)
for (kp = np; kp >= 0; kp--)
for (kc = nc; kc >= 0; kc--) {
if (ks == ns && kp == np && kc == nc)
x = 0;
else {
x = -INF;
if (ks < ns)
x = max(x, -dp[ks + 1][kp][kc] - (ks < ns2 ? 1 : 2));
if (kp < np)
x = max(x, min(-dp[ks][kp + 1][kc] - pp[kp] + 1, dp[ks][kp + 1][kc] - pp[kp] + 5));
if (kc < nc)
x = max(x, min(-dp[ks][kp][kc + 1] - cc[kc], dp[ks][kp][kc + 1] - cc[kc] + 8));
}
dp[ks][kp][kc] = x;
}
printf("%d\n", dp[0][0][0]);
return 0;
}
