biolean?)))
var x, y, z, k:integer;
begin
readln(x, y, z, k);
if k = x then
write('k равно x')
else if k = y then
write('k равно у')
else if k = z then
write('k равно z')
else
write(min(min(k-x, k-y), k-z));
end.
biolean?)))
var x, y, z, k:integer;
begin
readln(x, y, z, k);
if k = x then
write('k равно x')
else if k = y then
write('k равно у')
else if k = z then
write('k равно z')
else
write(min(min(k-x, k-y), k-z));
end.