The educational program (AHK Education) of the Aiz Broadcasting Association broadcasts a handicraft program for children, "Play with Tsukuro". Today is the time to make a rectangle with sticks, but I would like to see if I can make a rectangle using the four sticks I prepared. However, the stick must not be cut or broken.




Given the lengths of the four bars, write a program to determine if you can make a rectangle with all of them as sides.



Input

The input is given in the following format.


e1 e2 e3 e4


The input consists of one line and is given the integer ei (1 ≤ ei ≤ 100) representing the length of each bar.

Output

Outputs "yes" if a rectangle can be created, and "no" if it cannot be created. However, since a square is a type of rectangle, "yes" is output even if it is a square.

Examples

Input

1 1 3 4


Output

no


Input

1 1 2 2


Output

yes


Input

2 1 1 2


Output

yes


Input

4 4 4 10


Output

no
#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
typedef long long ll;
typedef pair<int,int> pii;
#define _overload4(_1,_2,_3,_4,name,...) name
#define _overload3(_1,_2,_3,name,...) name
#define _rep1(n) _rep2(i,n)
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(ll i=a;i<b;++i)
#define _rep4(i,a,b,c) for(ll i=a;i<b;i+=c)
#define rep(...) _overload4(__VA_ARGS__,_rep4,_rep3,_rep2,_rep1)(__VA_ARGS__)
#define _rrep1(n) _rrep2(i,n)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(ll i=b-1;i>=a;i--)
#define _rrep4(i,a,b,c) for(ll i=a+(b-a-1)/c*c;i>=a;i-=c)
#define rrep(...) _overload4(__VA_ARGS__,_rrep4,_rrep3,_rrep2,_rrep1)(__VA_ARGS__)
#define each(i,a) for(auto&& i:a)
#define sum(...) accumulate(range(__VA_ARGS__),0LL)
#define _range(i) (i).begin(),(i).end()
#define _range2(i,k) (i).begin(),(i).begin()+k
#define _range3(i,a,b) (i).begin()+a,(i).begin()+b
#define range(...) _overload3(__VA_ARGS__,_range3,_range2,_range)(__VA_ARGS__)
const ll LINF=0x3fffffffffffffff;
const ll MOD=1000000007;
const ll MODD=0x3b800001;
const int INF=0x3fffffff;
#define yes(i) out(i?"yes":"no")
#define Yes(i) out(i?"Yes":"No")
#define YES(i) out(i?"YES":"NO")
#define Possible(i)out(i?"Possible":"Impossible")
#define unless(a) if(!(a))
//#define START auto start=system_clock::now()
//#define END auto end=system_clock::now();cerr<<duration_cast<milliseconds>(end-start).count()<<" ms\n"
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;in(__VA_ARGS__)
#define vec(type,name,...) vector<type> name(__VA_ARGS__);
#define VEC(type,name,size) vector<type> name(size);in(name)
#define vv(type,name,h,w,value) vector<vector<type>>name(h,vector<type>(w,value))
#define pll pair<ll,ll>
struct SETTINGS{SETTINGS(){cin.tie(0); cout.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(20);};}SETTINGS;
template<typename T>
inline bool update_min(T& mn,const T& cnt){if(mn>cnt){mn=cnt;return 1;}else return 0;}
template<typename T>
inline bool update_max(T& mx,const T& cnt){if(mx<cnt){mx=cnt;return 1;}else return 0;}
template<typename T>
inline T max(vector<T>& vec){return *max_element(range(vec));}
template<typename T>
inline constexpr T gcd (T a,T b) {if(a==b)return a;else return gcd(b,(a-1)%b+1);}
inline void in() {}
template<typename T>
istream& operator >> (istream& is, vector<T>& vec);
template<typename T,size_t size>
istream& operator >> (istream& is, array<T,size>& vec);
template<typename T,typename L>
istream& operator >> (istream& is, pair<T,L>& p);
template<typename T>
ostream& operator << (ostream& os, vector<T>& vec);
template<typename T,typename L>
ostream& operator << (ostream& os, pair<T,L>& p);
template<typename T>
istream& operator >> (istream& is, vector<T>& vec){for(T& x: vec) is >> x;return is;}
template<typename T,typename L>
istream& operator >> (istream& is, pair<T,L>& p){is >> p.first;is >> p.second;return is;}
template<typename T>
ostream& operator << (ostream& os, vector<T>& vec){os << vec[0];rep(i,1,vec.size()){os << ' ' << vec[i];}return os;}
template<typename T>
ostream& operator << (ostream& os, deque<T>& vec){os << vec[0];rep(i,1,vec.size()){os << ' ' << vec[i];}return os;}
template<typename T,typename L>
ostream& operator << (ostream& os, pair<T,L>& p){os << p.first << " " << p.second;return os;}
template <class Head, class... Tail>
inline void in(Head&& head,Tail&&... tail){cin>>head;in(move(tail)...);}
template <typename T>
inline void out(T t){cout<<t<<'\n';}
inline void out(){cout<<'\n';}
template <class Head, class... Tail>
inline void out(Head head,Tail... tail){cout<<head<<' ';out(move(tail)...);}




signed main(){
    VEC(int,a,4);
    sort(range(a));
    yes(a[0]==a[1]&&a[2]==a[3]);
}








