Program num1;
Uses crt;
Var
x1,x2,y1,y2 : real;
d:real;
Begin
clrscr;
write('x1=');readln(x1);
write('y1=');readln(y1);
write('x2=');readln(x2);
write('y2=');readln(y2);
d:=sqrt(sqr(x2-x1)+sqr(y2-y1));
write('D=',d)
End.
Program num1;
Uses crt;
Var
x1,x2,y1,y2 : real;
d:real;
Begin
clrscr;
write('x1=');readln(x1);
write('y1=');readln(y1);
write('x2=');readln(x2);
write('y2=');readln(y2);
d:=sqrt(sqr(x2-x1)+sqr(y2-y1));
write('D=',d)
End.