矩阵快速幂模板

struct Matrix {
    int n , m , a[2][2];
    Matrix (int _n = 0, int _m = 0) {
        n = _n , m = _m;
        memset(a , 0 , sizeof(a));
    }
    Matrix operator * (const Matrix &R) const {
        Matrix res(n , R.m);
        for (int i = 0 ; i < n ; ++ i) {
            for (int j = 0 ; j < m ; ++ j) {
                for (int k = 0 ; k < R.m ; ++ k) {
                    res.a[i][k] += (LL)a[i][j] * R.a[j][k] % Q;
                    res.a[i][k] %= Q;
                }
            }
        }
        return res;
    }
};