modint

``` struct modint { ll x; modint() : x(0) {} modint(ll x) : x(x) {} bool operator==(modint y) { return x == y.x; } void operator=(int y) { y %= mod; / ......

modint by cjl ``` struct m{ int x;m(int o=0){x=o;}m(lll o){x=o%mod;}m&operator+=(m a){return(x+=a.x)%=mod,*this;}m&operator-=(m a){return(x+=mod-a.x)% ......