#include<stdio.h>
#include<stdlib.h>

#define STR_LENGTH 16
#define NUM_INPUT 4

void str_cut(char*, unsigned char*);

int main(void){
  unsigned char veg_num = 0;
  unsigned char veg_max = 0;
  char str[STR_LENGTH];
  unsigned char input[NUM_INPUT] = {0}; /* 入力を数値に変換したデータ保管 */

  fgets(str, sizeof(str), stdin);
  str_cut(str, input);

  veg_max = (unsigned char) (input[3] / (input[2] + 1));

  if(veg_max > input[0]){
    veg_max = input[0];
  }

  if((veg_max * input[2] <= input[1])){
    veg_num = veg_max;
  } else {
    veg_num = (unsigned char) (input[1] / input[2]);
  }

  printf("%d\n", veg_num);
  return 0;
}

/*
関数概要：渡された文字列を空白で分離し、数値に変換する
第1引数：文字列
第2引数：文字列から数値に変換して格納する配列
*/
void str_cut(char* str, unsigned char* input){
  int start_str = 0;
  int num = 0; //配列NO
  int i = 0;

  while('\0' != str[i]){
    if(' ' == str[i]){
      str[i] = '\0';
      input[num] = (unsigned char) atoi(&str[start_str]);
      ++num;
      ++i;
      start_str = i;
    }
    ++i;
  }

  input[num] = (unsigned char) atoi(&str[start_str]);

  return;
}