Charsi in Love

#include <stdio.h>
#include<math.h>
int binarySearch(int low,int high,int key)
{
    while(low<=high)
    {
        int mid=(low+high)/2;
        int x = (mid*(mid+1));
        if(x<key)
        {
            low=mid+1;
        }
        else if(x>key)
        {
            high=mid-1;
        }
        else
        {
            return mid;
        }
    }
    return -1;
}
 
int main()
{
    int n,i,j,b;
    int flag=0;
    scanf("%d",&n);
    for(i=1;i<=sqrt(n);i++){
        b = n - ((i*(i+1))/2);
        int y = binarySearch(1,sqrt(2*b),2*b);
        if(y>0) {
            flag =1;
            break;
        }
    }
    if(flag==1)
    printf("YES");
    else
    printf("NO");
    return 0;
}