// editor3
#include<stdio.h>
int main()
{
   int loe, high, sum = 0;
   scanf("%d %d", &low, &high);
   if (low < 1 || high < 1 || low > high)
   {
       printf("Invalid Input");
       return 0;
   }
   for (int i = low; i <=high; i++)
   {
       if (i % 7 == 0)
       sum += i;
   }
   
   printf("%d", sum);
   return 0;)
}