地址:http://acm.swust.edu.cn/problem/281/
#include<stdio.h>
int main()
{
int total,jump,drop;
while(scanf("%d%d%d",&total,&jump,&drop)!=EOF && total!=0 && jump!=0 && drop!=0)
{
int time,sum=0;
for(time=1;;time++)
{
sum=sum+jump;
if(sum>=total)
break;
time++;
sum=sum-drop;
if(sum>=total)
break;
}
printf("%d\n",time);
}
return 0;
}