A

每一个数字的欧拉函数要大于或等于该数字。求，最小的欧拉函数的下标和的大小。

答案要用longlong存

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <string>
#include <map>
#include <cmath>
#include <vector>

#define Faster ios::sync_with_stdio(false),cin.tie(0)
#define Read freopen("in.txt","r",stdin),freopen("out.txt","w",stdout)
#define Close fclose(stdin),fclose(stdout)
const int maxn = 1e6 + 5;
using namespace std;
const int MOD = 1e9+7;
typedef long long ll;

int a[maxn];
ll euler[maxn];
bool isPrime[maxn];
ll mp[maxn];

void Init(){     
     euler[1]=1;    
     for(int i=2;i<maxn;i++)    
       euler[i]=i;    
     for(int i=2;i<maxn;i++)    
        if(euler[i]==i)    
           for(int j=i;j<maxn;j+=i)    
              //euler[j]=euler[j]/i*(i-1);//先进行除法是为了防止中间数据的溢出     
              euler[j] -= euler[j] / i;
}

int main(){
    Faster;
    Init();
    int t;
    cin >> t;
    int cnt = 0;
    while(t--){
        cnt++;
        int n;
        cin >> n;
        ll ans = 0;
        for(int i = 0;i < n;i++){
            // int x;
            cin >> a[i];
        }
        sort(a, a+n);
        int j = 2;
        for(int i = 0;i < n;i++){
            for(;j < maxn;j++){
                if(euler[j] >= a[i]){
                    ans += j;
                    break;
                }
            }
        }
        cout << "Case " << cnt << ": " << ans << " Xukha" << endl; 
    }
    return 0;
}