#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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