#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main() {
    int m, n,sum=0,i;
    scanf("%d%d", &m,& n);
    if (0<=m&&m<=n&&n<=300)
    {
        for (m; m <=n; m++)
        {
            if (m % 2 != 0) {
                sum = sum + m;     
            } 
        }    
       printf("%d", sum);
    }

    return 0;
}