#include<iostream>
#include<cmath>
using namespace std;
int main()
{
int a,b,c;
cin>>a>>b>>c;
if(a+b>c&&a+c>b&&b+c>a)
cout<<"yes"<<endl;
else
cout<<"no"<<endl;
return 0; 
}

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
int a,b,c;
cin>>a>>b>>c;
if(a+b>c&&a+c>b&&b+c>a)
cout<<"yes"<<endl;
else
cout<<"no"<<endl;
return 0;
}
//👍