#include <iostream>
#include <algorithm>

using namespace std;

int main(){
	int ary[4];
	for(int i = 0; i < 4; i++){
		cin >> ary[i];
	}
	sort(ary , ary + 4 , greater<int>());
	if(ary[0] == ary[1] && ary[2] == ary[3]){
		cout << "yes" << endl;
	}else{
		cout << "no" << endl;
	}
	
	return 0;
}