#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <math.h>
int main(void)
{
    int vegitable,meat,times,total,caneat=0;
    scanf("%d %d %d %d",&vegitable,&meat,&times,&total);
    while(1)
    {
        if(vegitable<=0||meat<times||total<times+1)
        {
            break;
        }
        vegitable--;
        meat-=times;
        total-=(times+1);
        caneat++;
    }
    printf("%d",caneat);
}