#include<stdio.h>
int iter=2,n=2,number,end=3,count,array[673366];
int main()
{
    scanf("%d",&number);
    array[2]=3;
    if(number<=3)
    printf("%d",((number<=2)?number:2));
    else
    {
        while(number>end)
        {
			n++;
			if(array[iter]>=n)
                        count=iter;
            if(array[iter]==n)
                iter++;
            end+=count;
            array[n]=end;
        }
      printf("%d",n);
    }    
    scanf("%d",&n);
}