UVa 10392 - Factoring Large Numbers

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
long long  a,i,j,t,flag;
while(cin>>a&&a!=-1)
{
for(i=2; i<=1000000;i++)
{
while(!(a%i))
{
cout<<"    "<<i<<endl;
a=a/i;
}
if(a==1)
break;
}
if(i>1000000)
cout<<"    "<<a<<endl;
cout<<endl;
}
return 0;
}