var
  a, b, c: integer;
begin
  write('Vvedite a,b,c: ');
  readln(a, b, c);
  
  while a <> b do
    if a > b then a := a - b
    else b := b - a;
  
  while a <> c do
    if a > c then a  := a - c
    else c := c - a;
  
  writeln('Nod(a,b,c): ', a);
  readln;
end.