int n,m, bes = MOD;
string t[300000], ans[300000], tmp[300000];
string z = "ACGT";

string gen(vi v, int m) {
    string Z;
    F0R(i,m) Z += z[v[i&1]];
    return Z;
}

int dif(string a, string b) {
    int d = 0;
    F0R(i,sz(a)) if (a[i] != b[i]) d ++;
    return d;
}

void tri(int a, int b) {
    vi v[2];
    v[0] = {a,b};
    F0R(i,4) if (find(all(v[0]),i) == v[0].end()) v[1].pb(i);

    int cur = 0;
    F0R(i,n) {
        int x = dif(gen(v[i&1],m),t[i]);
        auto V = v[i&1]; swap(V[0],V[1]);
        int y = dif(gen(V,m),t[i]);
        if (x < y) {
            cur += x;
            tmp[i] = gen(v[i&1],m);
        } else {
            cur += y;
            tmp[i] = gen(V,m);
        }
    }

    if (cur < bes) {
        bes = cur;
        F0R(i,n) ans[i] = tmp[i];
    }
}

void tri2(int a, int b) {
    vi v[2];
    v[0] = {a,b};
    F0R(i,4) if (find(all(v[0]),i) == v[0].end()) v[1].pb(i);

    int cur = 0;
    F0R(i,m) {
        string tt; F0R(j,n) tt += t[j][i];
        int x = dif(gen(v[i&1],n),tt);
        auto V = v[i&1]; swap(V[0],V[1]);
        int y = dif(gen(V,n),tt);
        if (x < y) {
            cur += x;
            string zz = gen(v[i&1],n);
            F0R(j,n) tmp[j][i] = zz[j];
        } else {
            cur += y;
            string zz = gen(V,n);
            F0R(j,n) tmp[j][i] = zz[j];
        }
    }
    /*pr("AH",v[0],cur);
    F0R(i,n) pr(tmp[i]);
    pr("");*/

    if (cur < bes) {
        bes = cur;
        F0R(i,n) ans[i] = tmp[i];
    }
}

int main() {
    // you should actually read the stuff at the bottom
    setIO(); re(n,m);
    F0R(i,n) re(t[i]);
    F0R(i,4) FOR(j,i+1,4) {
        tri(i,j);
        tri2(i,j);
    }
    F0R(i,n) pr(ans[i]);
    // pr(bes);
    // you should actually read the stuff at the bottom
}