program xxx;
uses crt;
var x1,y1,x2,y2:integer;
      r:real;
BEGIN
clrscr;
writeln('Ââåäèòå êîîðäèíàòû òî÷êè A');
readln(x1,y1);
writeln('Ââåäèòå êîîðäèíàòû òî÷êè B');
readln(x2,y2);
r:=sqrt(sqr(x2-x1)+sqr(y2-y1));
writeln('r=',r:7:2);
readln;
END.