#include <fstream>
using namespace std;
ifstream f("simpla.in");
ofstream g("simpla.out");
int main()
{int s=0,p=0,a,b,i,r,c;
f>>a>>b;
for(i=a;i<=b;i++)
{r=i;
s=0;
	while(r!=0)
{c=r%10;
 r=r/10;
 s=s+c;
}
if(s%2==0)
	p+=1;
}
g<<p;
}