#include<stdio.h>
void main()
{
    int i,c[1225],sum=0,j,k;
    int a[]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,29,40,41,42,43,44,45,46,47,48,49,50};
    for(i=0,k=0;i<50;i++)
    {
        for(j=49;j>i&&k<1225;j--,k++)
        c[k]=a[i]&a[j];
    }
    for(i=0;i<1225;i++)
       {
           sum=sum+c[i];
       }
    printf("%d",sum);
}