题解 | #搬圆桌#

#include<stdio.h>
int main()
{
    long r,x,y,x1,y1;
    while(scanf("%ld %ld %ld %ld %ld",&r,&x,&y,&x1,&y1)!=EOF)
    {
        getchar();
        int bu;
         long d;
        int R=2*r;
        d=pow((x-x1)*(x-x1)+(y-y1)*(y-y1),0.5);
        int n=(int)(d/(2*r));
        if(n*2*r<d)
        {
            n=n+1;
        }
        printf("%d\n",n);
    }
    return 0;

 }