#include
#include
#include
using?namespace?std;
long?long?stabans;
long?long?f[1000005];
void?DP（）
{
	memset（f0x7fsizeof（f））;
	f[s]=0;
	for（int?i=s;i<=t;i++）
	{
		if（i*b<=t）
		??f[i*b]=min（f[i*b]f[i]+1）;
		if（i+a<=t）
		??f[i+a]=min（f[i+a]f[i]+1）;
	}
}
int?main（）
{
	freopen（“a.in““r“stdin）;
	freopen（“a.out““w“stdout）;
	scanf（“%lld%lld%lld%lld“&s&t&a&b）;
	if（a==1）
	{
		while（s		{
			if（t%b!=0）
			{
				ans+=t-t/b*b;
				t=t/b*b;
			}
			if（t/b			{
				ans+=t-s;
				break;
			}
			t/=b;
			ans++;
		}
		printf（“%lld\n“ans）;
		return?0;
	}
	DP（）;
	printf（“%lld\n“f[t]）;
}

?屬性????????????大小?????日期????時間???名稱
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?????目錄???????????0??2018-02-28?21:31??noi_day5\
?????目錄???????????0??2018-02-28?12:27??noi_day5\data\
?????目錄???????????0??2018-02-28?12:22??noi_day5\data\A\
?????文件??????????17??2018-02-28?01:11??noi_day5\data\A\1.in
?????文件???????????6??2018-02-28?01:11??noi_day5\data\A\1.out
?????文件??????????34??2018-02-28?01:05??noi_day5\data\A\10.in
?????文件??????????11??2018-02-28?01:05??noi_day5\data\A\10.out
?????文件??????????16??2018-02-28?01:11??noi_day5\data\A\2.in
?????文件???????????5??2018-02-28?01:11??noi_day5\data\A\2.out
?????文件??????????16??2018-02-28?01:11??noi_day5\data\A\3.in
?????文件???????????6??2018-02-28?01:11??noi_day5\data\A\3.out
?????文件??????????33??2018-02-28?01:10??noi_day5\data\A\4.in
?????文件??????????10??2018-02-28?01:10??noi_day5\data\A\4.out
?????文件??????????34??2018-02-28?01:10??noi_day5\data\A\5.in
?????文件??????????10??2018-02-28?01:10??noi_day5\data\A\5.out
?????文件??????????34??2018-02-28?01:09??noi_day5\data\A\6.in
?????文件??????????12??2018-02-28?01:09??noi_day5\data\A\6.out
?????文件??????????33??2018-02-28?01:05??noi_day5\data\A\7.in
?????文件???????????9??2018-02-28?01:05??noi_day5\data\A\7.out
?????文件??????????34??2018-02-28?01:06??noi_day5\data\A\8.in
?????文件??????????10??2018-02-28?01:06??noi_day5\data\A\8.out
?????文件??????????34??2018-02-28?01:09??noi_day5\data\A\9.in
?????文件??????????11??2018-02-28?01:09??noi_day5\data\A\9.out
?????目錄???????????0??2018-02-28?12:22??noi_day5\data\B\
?????文件????????3910??2018-02-28?00:24??noi_day5\data\B\1.in
?????文件????????9964??2018-02-28?00:25??noi_day5\data\B\1.out
?????文件????????9796??2018-02-27?21:11??noi_day5\data\B\10.in
?????文件????????9939??2018-02-27?21:22??noi_day5\data\B\10.out
?????文件????????9797??2018-02-28?00:24??noi_day5\data\B\2.in
?????文件????????9777??2018-02-28?00:25??noi_day5\data\B\2.out
?????文件????????1750??2018-02-28?00:20??noi_day5\data\B\3.in
............此處省略539個文件信息