> #include<stdio.h>     
> int main()     
> {     
>     int n,k;     
>     while(scanf("%d %d",&n,&k)!=EOF)     
>     {     
> 		int t=(n-k)/(k-1)+1;
> 		printf("%d\n",n+t);
>     }     
>     return 0 ;     
> }      


2 5
这组数据会出错
正确答案是2