#include <bits/stdc++.h>
using namespace std;
 
int hotness_level(int men[],int women[],int n){
  int sum=0;
	for(int i=0;i<n;i++){
		sum=sum+(men[i]* women[i]);
	}
	return sum;
}
int main() {
	int t;
	cin>>t;
	while(t--){
		int n;
		cin>>n;
		int men[n];
		int women[n];
		for(int i=0;i<n;i++){
			cin>>men[i];
		}
		for(int i=0;i<n;i++){
			cin>>women[i];
		}
 
		int total=hotness_level(men,women,n);
 
		cout<<total<<endl;
 
	}
	// your code goes here
	return 0;
}

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