public static string length(double m)
{
if (m >= 1000000000000000000)
return roundS(m / 1000000000000000000) + " E";
if (m >= 1000000000000000)
return roundS(m / 1000000000000000) + " P";
if (m >= 1000000000000)
return roundS(m / 1000000000000) + " T";
if (m >= 1000000000)
return roundS(m / 1000000000) + " G";
if (m >= 1000000)
return roundS(m / 1000000) + " M";
if (m >= 1000)
return roundS(m / 1000) + " k";
return roundS(m) + " ";
}