#include using namespace std; using ll = long long; using ld = long double; using VI = vector; using VL = vector; using VS = vector; template using PQ = priority_queue, greater>; #define FOR(i,a,n) for(int (i)=(a);(i)<(n);++(i)) #define eFOR(i,a,n) for(int (i)=(a);(i)<=(n);++(i)) #define rFOR(i,a,n) for(int (i)=(n)-1;(i)>=(a);--(i)) #define erFOR(i,a,n) for(int (i)=(n);(i)>=(a);--(i)) #define each(i, a) for(auto &i : a) #define SORT(i) sort((i).begin(),(i).end()) #define rSORT(i,a) sort((i).begin(),(i).end(),(a)) #define all(i) (i).begin(),(i).end() #define out(y,x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x)) #define line cout << "-----------------------------\n" #define ENDL(i,n) ((i) == (n) - 1 ? "\n" : " ") #define stop system("pause") constexpr ll INF = 1000000000; constexpr ll LLINF = 1LL << 60; constexpr ll mod = 1000000007; constexpr ll MOD = 998244353; constexpr ld eps = 1e-10; constexpr ld pi = 3.1415926535897932; templateinline bool chmax(T& a, T b) { if (a < b) { a = b; return true; }return false; } templateinline bool chmin(T& a, T b) { if (a > b) { a = b; return true; }return false; } inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } templateinline istream& operator>>(istream& is, vector& v) { for (auto& elemnt : v)is >> elemnt; return is; } templateinline istream& operator>>(istream& is, deque& v) { for (auto& elemnt : v)is >> elemnt; return is; } templateinline istream& operator>>(istream& is, pair& p) { is >> p.first >> p.second; return is; } templateinline vector vec(size_t a) { return vector(a); } templateinline vector defvec(T def, size_t a) { return vector(a, def); } templateinline auto vec(size_t a, Ts... ts) { return vector(ts...))>(a, vec(ts...)); } templateinline auto defvec(T def, size_t a, Ts... ts) { return vector(def, ts...))>(a, defvec(def, ts...)); } int main() { init(); VI a(4); cin >> a; SORT(a); bool ok = true; FOR(i, 0, 4)ok &= a[i] - a[0] == i; cout << (ok ? "Yes" : "No") << "\n"; }