#include<stdio.h>
#include<math.h>
struct Coordinate{
int x;
int y;
};
int main(void)
{ double a,b,c,d,e,f,Shortest_distance,m,n,g,h,i;
scanf("%d %d %d %d %d %d %d",&a
,&b
,&c
,&d
,&e
,&f
); struct Coordinate A={a,b};
struct Coordinate B={c,d};
struct Coordinate C={e,f};
m=(double)(B.y-C.y)/(B.x-C.x);
///n=(double)B.y-m*B.x;
///g=m*A.x-A.y+n;
///h=fabs(g);
///i=sqrt(m*m+1.0);
///Shortest_distance=h/i;
return 0;
}
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