#include <stdio.h>

int main(){
	long long leaf, fall;
	scanf("%lld%lld",&leaf,&fall);
	
	int start,between;
	scanf("%d%d",&start,&between);
	
	int month = 1;
	int ans = 0;
	while(0 < leaf){
		if(ans % 12 < start){
			leaf -= fall;
		}else if(ans % 12 >= start && ans % fall <= start + between % 12){
			leaf -= (fall *  2);
		}
		ans++;
		month++;
		month %= 12;
	}
	printf("%d",ans);
}