UVa 11150 Cola Solution

#include<stdio.h>
int main()
{
int n,i,r,p,b,tb;
while(scanf("%d",&n)==1)
{
tb=0;
if(n%3==2)
p=n+1;
else
p=n;
for(i=p;i>=3;i=b+r)
    {
    b=i/3;
    r=i%3;
    tb=tb+b;
    }
if(n%6==0)
n=n+1;
if((n+2)%6==0)
n=n+1;
printf("%d\n",n+tb);
}
return 0;
}