let input = ['15,3,2'];



let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);


let inputOne = gets().split(',').map(Number);


let b = 0; // Initial budged.
let c = 0; // The price of beer.
let e = 0; // Requeired empty cups for one free beer.

let beers = 0;
let freeBeers = 0;
let remainder = 0;
let returnFree = 0;
let allBeers = 0;
let addBeer = 0;


for (let i = 0; i < inputOne.length; i++) {

  b = inputOne[0];

  c = inputOne[1];

  e = inputOne[2];

}


if (2 <= b && b <= 100000 && 1 <= c && c <= b && 2 <= e && e <= b) {



while (b >= 1) {

    b -= c;

    beers += 1;

}


if (beers >= e) {

returnFree = beers / e;

remainder = beers % e;


while (returnFree >= 1)  {

  returnFree -= 1;

  freeBeers += 1;


}


remainder = freeBeers + remainder;


while (remainder + addBeer >= e) {

  remainder -= e;

  freeBeers += 1;

  addBeer += 1;

}


}


  allBeers = beers + freeBeers;

  print(allBeers);

}