int LCSReturns(const string& A, const string& B) {
    int total = 0;
    vector<vector<int>> cache(A.size() + 1, vector<int>(B.size() + 1)), reverse(A.size() + 2, vector<int>(B.size() + 2));
    vector<vector<bool>> insertion(A.size() + 2, vector<bool>(75));
    for (int i = 1; i <= A.size(); i++) {
        for (int j = 1; j <= B.size(); j++) {
            if (A[i - 1] == B[j - 1]) cache[i][j] = cache[i - 1][j - 1] + 1;
            else cache[i][j] = max(cache[i - 1][j], cache[i][j - 1]);
        }
    }
    for (int i = A.size(); i >= 1; i--) {
        for (int j = B.size(); j >= 1; j--) {
            if (A[i - 1] == B[j - 1]) reverse[i][j] = reverse[i + 1][j + 1] + 1;
            else reverse[i][j] = max(reverse[i + 1][j], reverse[i][j + 1]);
        }
    }
    for (int i = 1; i <= A.size() + 1; i++) {
        for (int j = 1; j <= B.size(); j++) {
            if (insertion[i][B[j - 1] - '0']) continue;
            if (cache[i - 1][j - 1] + reverse[i][j + 1] == cache[A.size()][B.size()]) {
                insertion[i][B[j - 1] - '0'] = true;
                total++;
            }
        }
    }
    return total;
}