n;p;i;j;
a;b;c;
e;

d[15010];

min(a,b){return a<b?a:b;}

main(){
	scanf("%d%d",&n,&p);
	for(i=0;i<n;++i){
		scanf("%d%d%d",&a,&b,&c);
		for(j=p;j>=0;j--){
			d[j]+=a;
			if(j>=1&&d[j]>d[j-1]+b)d[j]=d[j-1]+b;
			if(j>=2&&d[j]>d[j-2]+c)d[j]=d[j-2]+c;
			if(j>=3&&d[j]>d[j-3]+1)d[j]=d[j-3]+1;
		}
	}
	printf("%.8f",(double)d[p]/n);
	return 0;
}