#define V(x) vector<x >

#define vs V(string)

#define vi V(int)

#define fr(x,y,z) for ((x)=(y);(x)<(z);(x)++)

#define fo(x,y) fr(x,0,y)

#define fir(n) fo(i,n)

#define fjr(n) fo(j,n)

#define fkr(n) fo(k,n)

#define fi fir(n)

#define fj fjr(n)

#define fk fkr(n)

#define pb push_back

#define sz size()

#define cs c_str()

#define df double