C++ :

#include <iostream>
#include <climits>
using namespace std;
int main() {
	int l, r;
  cin >> l >> r;
  int sum = 0;
  for (int i = l; i <= r; ++i) {
  	if (i % 2 == 1) sum += i;  
  }
	cout << sum;
  return 0;
}