PascalABC.NET
// 1
begin
var p: int64 := 1;
for var i := 2 to 20 do
p *= i;
Println(p)
end.
//2
begin
var (k, d) := (0, 1);
while d <> 0 do
begin
Read(d);
if d <> 0 then
k += 1
end;
Println(k);
end.
// 3
begin
var (s, d) := (0, 1);
while d <> 0 do
begin
Read(d);
if d.IsEven then
s += d
end;
Println(s);
end.
