#include <bits/stdc++.h>
using namespace std;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	auto read = [&](){
		int x; cin >> x;
		return x;
	};
	vector<int> a(4);
	for(int & v : a) v = read();
	sort(a.begin(), a.end());
	if(a[0] + a[3] == a[1] + a[2] || a[3] == a[0] + a[1] + a[2]) cout << "Yes\n";
	else cout << "No\n";
	return 0;
}

#include <iostream>

using namespace std;

int main()
{
    string x;
    cin >> x;
    int i=0;
    for(int i=0; i<x.length(); i++){
        if( ( (i%2!=0)&&(x[i]>='a')&&(x[i]<='z') ) || ( (i%2==0)&&(x[i]>='A')&&(x[i]<='Z') ) ) {
            cout << "No";
            return 0;
        }
    }
    cout << "Yes";

    return 0;
}
