C++ :

#include<stdio.h>

int main()
{
	int a,b,c;
	scanf("%d%d%d",&a,&b,&c);
	
	if(a+b>c and a+c>b and c+b>a)
	{
		printf("yes");
	}
	
	
	if(a+b<=c or a+c<=b or c+b<=a)
	{
		printf("no");
	}
	
}