矩阵快速幂

struct Matrix
{
    int mm[3][3];
    Matrix() { memset(mm, 0, sizeof(mm)); }
    void init(){
        for (int i = 0; i < 3; ++i)
            for (int j = 0; j < 3; ++j) mm[i][j] = (i == j);
    }
    Matrix operator * (const Matrix &p)const {
        Matrix C;
        for (int i = 0; i < 3; ++i) {
            for (int j = 0; j < 3; ++j) {
                C.mm[i][j] = 0;
                for (int k = 0; k < 3; ++k)
                    C.mm[i][j] = (C.mm[i][j] + 1LL * mm[i][k] * p.mm[k][j] % MOD) % MOD;
            }
        }
        return C;
    }
    Matrix operator ^ (ll &p) {
        Matrix res, x = *this;
        res.init();
        while (p) {
            if (p & 1) res = res * x;
            x = x * x;
            p >>= 1;    
        }
        return res;
    }
} ;