UVA_11136_Hoax_Or_What

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <sstream>
#include <stdlib.h>
#include <cmath>
#define LL unsigned long long
using namespace std;

int main() {
    multiset <long long int> ms;

    int t;int n;long long int p;long long int mini;long long int maxi;
    while(scanf("%d",&t)){
        if(t==0) break;long long int sum=0;
                maxi=0;mini=0;
        for(int i=0;i<t;i++){
                   scanf("%d",&n);
            for(int j=0;j<n;j++){
             cin>>p;ms.insert(p);

            }
            /*final del dia*/
            multiset <long long int> ::iterator it;
            it=ms.begin(); mini=*it; ms.erase (it);
            it=ms.end();--it;maxi=*it;ms.erase(it);
            sum+=(maxi-mini);
        }
        printf("%ld\n",sum);
        ms.clear();
    }
    return 0;
}