Method Mod

code/mathematics/berlekamp_massey.test.cpp:6–8

struct Mod {
    ll x;
    Mod(ll _x = 0) {
        x = (_x % 1000000007 + 1000000007) % 1000000007;
    }
    Mod operator +(const Mod &other) const {
        return x + other.x;
    }