#include<stdio.h>
int main ()
{
long long int a , b, c=0 , d=0 ,e=0 ,i , j , k ,l ,sum=0 , n;
scanf("%lld" , &n) ;
for(i=2;;i=i+2)
{
sum=sum+i ;
e++ ;
if(sum>n)
{
sum = sum-i ;
break ;
}
}
b= n-sum ;
if(b==0)
e-- ;
k=e%2 ;
if(k==0)
{
if(b==0)
printf("2") ;
else
{
for(j=e*4 ; ;j=j-2)
{
c++ ;
if(c==b)
{
printf("%lld" , j) ;
break;
}
}
}
}
else
{
if(b==0)
printf("%lld" , e*4) ;
for(l=2;;l=l+2)
{
d++ ;
if(b==d)
{
printf("%lld" , l) ;
break ;
}
}
}
return 0 ;
}
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