// Cost of balloons
// Sample code to perform I/O:

process.stdin.resume();
process.stdin.setEncoding("utf-8");
var stdin_input = "";

process.stdin.on("data", function (input) {
    stdin_input += input;                               // Reading input from STDIN
});

process.stdin.on("end", function () {
   main(stdin_input);
});

function main(input) {
    process.stdout.write(costBallons(input));       // Writing output to STDOUT
}

// Warning: Printing unwanted or ill-formatted data to output will cause the test cases to fail



// Write your code here
// Sample code to perform I/O:
//Enter your code here
function costBallons(data) {
    
    data= data.toString().split("\n");
    let answer =[];

    let ligne = 0;
    // Number of test    
    let tests = Number(data[ligne]);
    //console.log("Number of tests ", tests);
    ligne = 1;
    for (let t=1; t<=tests; t++ ) {
      //  console.log("Num test : ", t);
        
       // console.log(" ----- Cost ------ ");
        
        let costs = data[ligne].split(" ").map((item)=> Number(item));
        //for (let costX = 0; costX<costs.length; costX++) {
        //    console.log(costs[costX]);
            
        //}

        //console.log(" ----- Participants ------ ");
        ligne = ligne + 1;
        let participants =  Number(data[ligne]);
        ligne = ligne +1;
        //console.log(participants);
        let sumColone1=0;
        let sumColone2 = 0;
        //console.log(" ----- Status ------ ");
        for (let status=0; status<participants; status++) {
            let stat  = data[ligne+status].split(" ").map((item)=> Number(item));
          //  console.log(stat);
            // Calcul somme colonne 
            sumColone1 = sumColone1 + stat[status,0];
            sumColone2 = sumColone2 + stat[status,1];
            
        }
        //console.log(sumColone1);
        //console.log(sumColone2);

        // Cost green and cost purple
        costGreen = costs[0];
        costPurple = costs[1];

        // Case 1 
        sum1 = costGreen*sumColone1 + costPurple*sumColone2;
        //console.log(sum1);
        // Case 2 
        sum2 = costPurple*sumColone1 + costGreen*sumColone2; 
        //console.log(sum2);
        // 
        answer.push(Math.min(sum1,sum2));

        ligne = ligne +participants;
        

    }
    
    //let participants = Number(data[2]);
    //let status = 

    
    return answer.join("\n").toString();

}