Problem:
Score : 400 points

Problem Statement

You are going out for a walk, when you suddenly encounter N monsters. Each monster has a parameter called health, and the health of the i-th monster is h_i at the moment of encounter. A monster will vanish immediately when its health drops to 0 or below.

Fortunately, you are a skilled magician, capable of causing explosions that damage monsters. In one explosion, you can damage monsters as follows:

Select an alive monster, and cause an explosion centered at that monster. The health of the monster at the center of the explosion will decrease by A, and the health of each of the other monsters will decrease by B. Here, A and B are predetermined parameters, and A > B holds.

At least how many explosions do you need to cause in order to vanish all the monsters?

Constraints

All input values are integers.

1 ≤ N ≤ 10^5

1 ≤ B < A ≤ 10^9

1 ≤ h_i ≤ 10^9

Input

Input is given from Standard Input in the following format:

N A B
h_1
h_2
:
h_N

Output

Print the minimum number of explosions that needs to be caused in order to vanish all the monsters.

Sample Input 1

4 5 3
8
7
4
2

Sample Output 1

2

You can vanish all the monsters in two explosion, as follows:

First, cause an explosion centered at the monster with 8 health. The healths of the four monsters become 3, 4, 1 and -1, respectively, and the last monster vanishes.

Second, cause an explosion centered at the monster with 4 health remaining. The healths of the three remaining monsters become 0, -1 and -2, respectively, and all the monsters are now vanished.

Sample Input 2

2 10 4
20
20

Sample Output 2

4

You need to cause two explosions centered at each monster, for a total of four.

Sample Input 3

5 2 1
900000000
900000000
1000000000
1000000000
1000000000

Sample Output 3

800000000

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

//#define _AOJ_


        /*vvv>
        zzzzzI
 .---.  zzuzuI                 .vgggg&,.
+++++=  dAC:|I  .WbbWo       JMM9^```?TMB`  ..&gNNg,.   gggggggJ,   qgggggggg] (&&&&&&&&[   c+OA&J,   (&&&&&&+J,   .cJeAA&-.  (&&&&&&&&x   .&AA&=-.
+++++=  dTqk|I  Xpbpbp      JM#`           (M#^   ?MMp  MM|   +TMN. JMF      ' |yk      ` dVY    7Vk,  Vy     XV  cVf     ?Y!  JM         V$      `
+++++=  dcf:|I  Xppppp      dMN           .MM+     .MM  MM|     MM] JMMMMMM+   |@tqkoh)  ,y0      (V$  yyyyyyyV7  VV           JMWyZWr    TWVVVVW&,
++++++  d7qk|0  Xppppp      ^HMN,    _.db  WMm,   .MMF  MM|   ..MM` JMF      . |yk       .WV&.   .XW'  yy   4yn.  jyn      +.  JM                #S
`++++`  ?ZZZX=  ?WWWW=        -THMMMMH9^    (TMMMMM9!   MMMMMMM""   JMMMMMMMME |UU.        ?TUUUUY=    UU.   (UU-  ^7TUUUV7!   JUUUUUUUU  7TUNKO*/

#include "bits/stdc++.h"
using namespace std;
typedef long long lint;
typedef long double ld;
typedef string cs;
typedef vector<lint> liv;
//#define rep(i,n) for(int i=0;i<n;++i)
#define all(v) v.begin(),v.end()

#define pb push_back
#define _vcppunko4(tuple) _getname4 tuple
#define _getname4(_1,_2,_3,_4,name,...) name
#define _getname3(_1,_2,_3,name,...) name
#define _trep2(tuple) _rep2 tuple
#define _trep3(tuple) _rep3 tuple
#define _trep4(tuple) _rep4 tuple
#define _rep1(n) for(lint i=0;i<n;++i)
#define _rep2(i,n) for(lint i=0;i<n;++i)
#define _rep3(i,a,b) for(lint i=a;i<b;++i)
#define _rep4(i,a,b,c) for(lint i=a;i<b;i+=c)
#define _trrep2(tuple) _rrep2 tuple
#define _trrep3(tuple) _rrep3 tuple
#define _trrep4(tuple) _rrep4 tuple
#define _rrep1(n) for(lint i=n-1;i>=0;--i)
#define _rrep2(i,n) for(lint i=n-1;i>=0;--i)
#define _rrep3(i,a,b) for(lint i=b-1;i>=a;--i)
#define _rrep4(i,a,b,c) for(lint i=a+(b-a-1)/c*c;i>=a;i-=c)
template<class T>
istream& operator>>(istream& is,vector<T>& vec);
template<class T,size_t size>
istream& operator>>(istream& is,array<T,size>& vec);
template<class T,class L>
istream& operator>>(istream& is,pair<T,L>& p);
template<class T>
ostream& operator<<(ostream& os,vector<T>& vec);
template<class T,class L>
ostream& operator<<(ostream& os,pair<T,L>& p);
template<class T>
istream& operator>>(istream& is,vector<T>& vec){ for(T& x: vec) is>>x;return is; }
template<class T,class L>
istream& operator>>(istream& is,pair<T,L>& p){ is>>p.first;is>>p.second;return is; }
template<class T,class L>
ostream& operator<<(ostream& os,pair<T,L>& p){ os<<p.first<<" "<<p.second;return os; }

inline void in(){}
template <class Head,class... Tail>
inline void in(Head&& head,Tail&&... tail){ cin>>head;in(move(tail)...); }
inline bool out(){ cout<<'\n';return 0; }
template <class T>
inline bool out(T t){ cout<<t<<'\n';return 0; }
template <class Head,class... Tail>
inline bool out(Head head,Tail... tail){ cout<<head<<' ';out(move(tail)...);return 0; }
inline void ssize(lint s){}
template <class Head,class... Tail>
inline void ssize(lint s,Head&& head,Tail&&... tail){ head.resize(s);ssize(s,move(tail)...); }

#define rep(...) _vcppunko4((__VA_ARGS__,_trep4,_trep3,_trep2,_rep1))((__VA_ARGS__))
#define rrep(...) _vcppunko4((__VA_ARGS__,_trrep4,_trrep3,_trrep2,_rrep1))((__VA_ARGS__))

template<class T>
ostream& operator<<(ostream& os,vector<T>& vec){ os<<vec[0];rep(i,1,vec.size())os<<' '<<vec[i];return os; }
template<class T>
ostream& operator<<(ostream& os,deque<T>& deq){ os<<deq[0];rep(i,1,deq.size())os<<' '<<deq[i];return os; }

#define each(v) for(auto &e:v)
#define lin(...) lint __VA_ARGS__;in(__VA_ARGS__)
#define stin(...) string __VA_ARGS__;in(__VA_ARGS__)
#define vin(type,name,size) vector<type> name(size);in(name)
#define fi e.first
#define se e.second
#define YES(c) cout<<((c)?"YES\n":"NO\n"),0
#define Yes(c) cout<<((c)?"Yes\n":"No\n"),0
#define POSSIBLE(c) cout<<((c)?"POSSIBLE\n":"IMPOSSIBLE\n"),0
#define Possible(c) cout<<((c)?"Possible\n":"Impossible\n"),0
#define o(p) cout<<p<<endl,0
#define sp(p) cout<<p<<" "
#define no(p) cout<<p
#ifdef __ENV_TQK__
#define deb(p) cout<<p<<endl,0
#else
#define deb(p) 0
#endif
#define dd(n) cout<<fixed<<setprecision(n)
//mint
#define md_tmp template<uint_fast64_t md=1000000007>
md_tmp class mint{
	using u64=uint_fast64_t;

public:
	u64 a;

	constexpr mint(const u64 x=0) noexcept: a(x%md){}
	constexpr u64 &value() noexcept{ return a; }
	constexpr const u64 &value() const noexcept{ return a; }
	constexpr mint operator+(const mint rhs) const noexcept{
		return mint(*this)+=rhs;
	}
	constexpr mint operator-(const mint rhs) const noexcept{
		return mint(*this)-=rhs;
	}
	constexpr mint operator*(const mint rhs) const noexcept{
		return mint(*this)*=rhs;
	}
	constexpr mint operator^(const lint rhs) const noexcept{
		return mint(*this)^=rhs;
	}
	constexpr mint operator/(const mint rhs) const noexcept{
		return mint(*this)/=rhs;
	}
	constexpr mint &operator+=(const mint rhs) noexcept{
		a+=rhs.a;
		if(a>=md)a-=md;
		return *this;
	}
	constexpr mint &operator-=(const mint rhs) noexcept{
		if(a<rhs.a)a+=md;
		a-=rhs.a;
		return *this;
	}
	constexpr mint &operator*=(const mint rhs) noexcept{
		a=a*rhs.a%md;
		return *this;
	}
	constexpr mint &operator^=(const lint rhs) noexcept{
		if(!rhs)return *this=1;
		u64 exp=rhs-1;
		mint base=this->a;
		while(exp){
			if(exp&1)*this*=base;
			base*=base;
			exp>>=1;
		}
		return *this;
	}
	constexpr mint &operator/=(const mint rhs) noexcept{
		a=(*this*(rhs^(md-2))).a;
		return *this;
	}
};
md_tmp istream& operator>>(istream& os,mint<md>& m){
	os>>m.a,m.a%=md;
	return os;
}
md_tmp ostream& operator<<(ostream& os,const mint<md>& m){
	return os<<m.a;
}
md_tmp mint<md> ncr(lint n,lint r){
	if(n<r||n<0||r<0)return mint<md>(0);
	mint<md>ncr_res=1,ncr_div=1;
	rep(r)ncr_res*=(n-i),ncr_div*=(r-i);
	return ncr_res/ncr_div;
}
#ifndef _AOJ_
mint<> operator""m(unsigned long long n){ return mint<>(n); }
mint<998244353> operator""m9(unsigned long long n){ return mint<998244353>(n); }
mint<1000003> operator""m3(unsigned long long n){ return mint<1000003>(n); }
#endif
using mi=mint<>;

////P
//class P{ public:lint f,s; constexpr P(lint a,lint b):f(a),s(b){};constexpr P():f(0),s(0){}; };
//istream& operator>>(istream& is,P& p){ is>>p.f>>p.s;return is; }
//ostream& operator<<(ostream& os,const P& p){ return os<<p.f<<" "<<p.s<<endl; }
//bool operator<(const P& l,const P& r){ return(l.f-r.f?l.f<r.f:l.s<r.s); }
//bool operator>(const P& l,const P& r){ return(l.f-r.f?l.f>r.f:l.s>r.s); }
struct C{ lint f,s,t; };
bool operator<(const C& l,const C& r){ return l.t<r.t; }
bool operator>(const C& l,const C& r){ return l.t>r.t; }

//const
#define linf 1152921504606846976
//#define inf linf//INT_MAX
#define MAXN 330
#define md_1e9_7 1000000007
#define md_998244353 998244353
#define pi 3.14159265358979323846
//#define mod md_1e9_7

const int d4[5]={0,1,0,-1,0};

//funcs
#define compare(T,s) [](T l,T r){return(s);}

inline void eraseunique(string &v){//nの変更を忘れるな
	v.erase(unique(all(v)),v.end());
}

template<typename T>
vector<pair<T,lint>> runlength(vector<T> v){
	lint n=v.size();
	vector<pair<T,lint>> ret(1,{v[0],1});
	rep(i,1,n){
		if(ret[ret.size()-1].first==v[i])++ret[ret.size()-1].second;
		else ret.push_back({v[i],1});
	}
	return ret;
}

template<typename T,class F>//ラムダ式の受け取り方
vector<T> ruiseki(vector<T> a,F f,lint e){
	lint n=a.size();
	vector<T> s(n+1);
	rep(n)s[i+1]=f(s[i],a[i]);
	return s;
}

set< lint > divisor(lint n){
	set< lint > ret;
	for(lint i = 1; i * i <= n; i++){
		if(n % i == 0){
			ret.insert(i);
			if(i * i != n) ret.insert(n / i);
		}
	}
	return (ret);
}


//\funcs

int main(){
	lint n,a,b;in(n,a,b);
	vector<lint>h(n),g;in(h);
	auto fulfill=[&n,&a,&b,&h,&g](lint m){//m回で殺せる
		g=h;
		rep(n)g[i]-=b*m;
		lint need=0;
		rep(n){
			if(g[i]>0)need+=(g[i]+a-b-1)/(a-b);
		}
		return m>=need;
	};
	lint ok=1e18,ng=-1,cen;
	while(abs(ok-ng)>1)cen=(ok+ng)/2,(fulfill(cen)?ok:ng)=cen;
	o(ok);
}



//sub-EOF