program nodnok;
var a,b:longint;
function NOD(x,y:longint):longint;
begin if x<>0 then NOD:= NOD(y mod x,x) else NOD:= y;
end;
Begin Write('Введите a и b: ');
Readln(a,b);
Writeln('НОД ',a,' и ',b,' = ', NOD(a,b));
Readln;
End.