#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int i,b,c=0,d; cin>>b>>d; for(i=b;i<=d;i++){ if(i%13==0){ c+=i; } } cout<<c; return 0; }