/*  func02.c  */

#include <stdio.h>
#include <math.h>

double dist(double x1,double y1,double x2,double y2)
{
    double d;
    d=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
    return d;
}

int main(void)
{
    int i;
    double x1,x2,x3,y1,y2,y3;
    double ds;
    printf("No.1 [x,y] : ");
    scanf("%lf %lf",&x1,&y1);
    printf("No.2 [x,y] : ");
    scanf("%lf %lf",&x2,&y2);
    printf("No.3 [x,y] : ");
    scanf("%lf %lf",&x3,&y3);
    ds=0;
    ds=ds+dist(x1,y1,x2,y2);
    ds=ds+dist(x2,y2,x3,y3);
    ds=ds+dist(x3,y3,x1,y1);
    printf("nagasa=%f\n",ds);

    return 0;
}