C++ :

#include<bits/stdc++.h>
using namespace std;
int a,b,c,aa,bb,cc;
int main()
{
	cin>>a>>b>>c;
    aa=a+b;
    bb=a+c;
    cc=b+c;
    if(aa>c&&bb>b&&cc>a){
    	cout<<"yes";
    }
    else{
    	cout<<"no";
    }
}