program Project2;
{$APPTYPE CONSOLE}
var X1,X2,Y1,Y2,L:REAL;
begin
WRITELN('Vvedit koordynaty tochok X1,Y1,X2,Y2');
READLN(X1,Y1,X2,Y2);
L:=SQRT((SQR(X2-X1))+(SQR(Y2-Y1)));
WRITELN('Vidstan mij tochkamy L=',L:4:2);
READLN;
end.