#define ld long double
#define ite iterator
#define mp make_pair
#define ff first
#define ss second
#define pb push_back
#define ioS ios::sync_with_stdio(false);
#define fr(i,x,n) for(int i=x;i<n;i++)
#define re0 return 0 ;
#define mod 1000000007
#define cina(a,n) for(i=0;i<n;i++)cin >> a[i];
#define couta(a,n) for(i=0;i<n;i++)cout << a[i] << " ";