UVA 10791(p317)----Minimum Sum LCM

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
const int  maxn=1000000;
int n,num=0,cas=0;
int prime[maxn+50];
int v[maxn+50];
int p[maxn+50];
void prepare()
{
memset(v,0,sizeof(v));
for(int i=2; i<=maxn; i++)
{
if(!v[i])
for(int  j=2*i; j<=maxn; j+=i)
v[j]=1;
}
for(int i=2; i<=maxn; i++)
if(!v[i]) prime[num++]=i;
}
void solve(int n)
{
int check=0;
for(int i=0; i<num; i++)
{
int flag=0;
while(n%prime[i]==0)
{
flag=1;
p[i]++;
n/=prime[i];
//cout<<n<<endl;
}
if(flag) check++;
if(n==1) break;
}
long long sum=0;
//cout<<num<<endl;
for(int i=0; i<num; i++)
if(p[i])
{
sum+=pow(prime[i],p[i]);
// cout<<sum<<endl;
}
if(check<2) sum++;
if(n>1) sum+=n;
printf("Case %d: %lld\n",++cas,sum);
}
int main()
{
prepare();
while(scanf("%d",&n)==1&&n)
{
memset(p,0,sizeof(p));
if(n==1) printf("Case %d: %d\n",++cas,2);
else solve(n);
}
return 0;
}