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