#include <cstdio>
int main(){
    int A,B,C,D,ans=0;
    scanf("%d %d %d %d",&A,&B,&C,&D);
    while(true){
        if(A>0 && B>=C && D>=1+C){
        ans++;A--;B-=C;D=D-(1+C);
        }else break;
    }
    printf("%d\n",ans);
    return 0;
}