If you need a structure for modular numbers, here is my: ~~~~~ const int MOD = 1e9 + 7; //Or your one

struct Number { int value; Number (int value) { this->value = (MOD + value) % MOD; }

friend bool operator< (const Number& a, const Number& b) {
    return a.value < b.value;
}

friend bool operator== (const Number& a, const Number& b) {
    return a.value == b.value;
}

friend Number operator+ (const Number& a, const Number& b) {
    return Number ((a.value + b.value) % MOD);
}

friend Number operator- (const Number& a, const Number& b) {
    return Number ((a.value - b.value + MOD) % MOD);
}

friend Number operator* (const Number& a, const Number& b) {
    return Number (int(1LL * a.value * b.value % MOD));
}

friend Number operator^ (const Number& a, const Number& k) {
    if (k == 0) return 1;
    if (k == 1) return a;
    Number res = a ^ Number (k.value/2);
    return res * res * Number(k.value%2);
}


Number (int a, int k) {
    if (k == 0) this->value = 1;
    else if (k == 1) this->value = a;
    else {
        Number res = Number (a, k/2);
        res = res * res * Number(a, k%2);
        this->value = res.value;
    }
}

friend Number operator/ (const Number& a, const Number& b) {
    return a * Number(b.value, MOD - 2);
}

friend ostream& operator<<(ostream& os, const Number& a) {
    os << a.value;
    return os;
}

}; ~~~~~