program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  a, b, x, c, d: int64;       .

begin
  x:=0;
  readln(a,b,c,d);

  if (a = 0) and (b = 0) then
    writeln('INF')
    else
      if (a = 0) or ((b mod a) <> 0) or(c * (-b div a) + d = 0) then
        writeln('NO')
      else
        writeln(-b div a);

  readln;
  readln;
end.