#include <stdio.h>
void get_num(int num, int* psum)
{
    if (num != 0)
    {
        get_num(num / 10, &(*psum));
        *psum += num % 10;
    }
}
int main() 
{
    int l = 0;
    int r = 0;
    while (scanf("%d %d", &l, &r) != EOF)
    {
        int cnt = 0;
        for (int i = l; i <= r; i++)//先要产生数
        {
            int sum = 0;
            get_num(i, &sum);
            if (sum % 5 == 0)
            {
                cnt++;
            }
        }
        printf("%d\n", cnt);
    }
    return 0;
}