> #include<stdio.h>
> main()
> {
>       int i,n,r;
>       while(scanf("%d",&n)!=EOF)
>       {
>           r=0;
>           for(i=1;;i++)
>           {
>               r+=i;
>               if(r>=n)
>               break;
>           }
>           if((r-n)%2)
>           {
>               if(i%2)
>               i+=2;
>               else
>               i+=1;
>           }
>           printf("%d\n",i);
>       }
> }    
> //一句话,找规律