#include <iostream>
using namespace std;
int main() {
 
	ios::sync_with_stdio(false);
	cin.tie(NULL);
 
	int t;
	cin>>t;
	while(t--){
		int g,p,n;
		cin>>g>>p>>n;
		int sol[n][2];
		for(int i=0; i<n; ++i){
			for(int j=0; j<2; ++j){
				cin>>sol[i][j];
			}
		}
		int sum1=0,sum2=0;
		for(int i=0; i<n; ++i){
 
			sum1=sum1+(sol[i][0] * g)+(sol[i][1] * p);
			sum2=sum2+(sol[i][0] * p)+(sol[i][1] * g);
 
		}
		cout<<min(sum1,sum2)<<'\n';
 
	}
 
	return 0;
}

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2
9 6
10
1 1
1 1
0 1
0 0
0 1
0 0
0 1
0 1
1 1
0 0
1 9
10
0 1
0 0
0 0
0 1
1 0
0 1
0 1
0 0
0 1
0 0