#include<iostream>

using namespace std;

int main()

{

int n,m,i,sum=0;

cout<<"請輸入起始值及終止值";

cin>>n>>m; 

if(n%2==0) n++;

i=n;

while(i<=m){

sum+=i; 

i+=2;

}

cout<<sum;

return 0;

 }