poj 2407 Relatives

#include <iostream>

using namespace std;
int main()
{
long long bigNum,i,cnt,ans;
while(cin>>bigNum&&bigNum)
{
cnt = 0;
ans = bigNum;
while(bigNum != 1)
{
//cout<<bigNum<<endl;
for(i = 2;i <= bigNum;i ++)
{
if(bigNum % i == 0)
{
bigNum /= i;
if(i != cnt){
ans = ans /i *(i-1);
cnt = i;}
break;
}
}
}
cout<<ans<<endl;
}
return 0;
}