function Main(input){
  input = input.split(" ");
  var a = parseInt(input[0],10);
  var b = parseInt(input[1],10);
  var t = parseFloat(input[2],10)+0.5;
  var sum = 0;
  var tmp = 0;
  
  while(tmp<t){
        sum += a;
        tmp = tmp+b;
}
  console.log(sum);
}
Main(require("fs").readFileSync("/dev/stdin","utf-8"));