#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b,c;
	cin>>a>>b>>c;
	if(a<b) swap(a,b);
	if(a<c) swap(a,c);
	if(b<c) swap(b,c);
	if(b+c>a){
		cout<<"YES";
	}else{
		cout<<"NO";
	}
}
/**************************************************************
	Problem: 1045
	User: linzihang
	Language: C++
	Result: Wrong Answer
****************************************************************/