struct RGB {
  int red;
  int green;
  int blue
}

struct GrayScale {
  int lightness;
  int average;
  int luminosity
}

int div (int a, int b) {
  var count = 0;
  var cur_num = a;
  while (cur_num - b >= 0) {
    cur_num = cur_num - b;
    count = count + 1;
  }
  return count;
}

int max (int a, int b, int c) {
  var m = 0;
  if (a > b) {
    m = a;
  } else {
    m = b;
  }

  if (c > m) {
    m = c;
  }

  return m;
}

int min (int a, int b, int c) {
  var m = 300;
  if (a < b) {
    m = a;
  } else {
    m = b;
  }

  if (c < m) {
    m = c;
  }

  return m;
}

GrayScale rgbtogray (RGB rgb) {
  var maxNum = max(rgb.red, rgb.green, rgb.blue);
  var minNum = min(rgb.red, rgb.green, rgb.blue);

  var maxmin = maxNum + minNum;
  var light = div(maxmin, 2);

  var averageSum = rgb.red + rgb.green + rgb.blue;
  var ave = div(averageSum, 3);

  var luminositySum = (rgb.red * 21) + (rgb.green * 72) + (rgb.blue * 7);
  var lum = luminositySum;

  var gray = new GrayScale { lightness = light; average = ave; luminosity = lum };
  return gray;
}

global rgb = RGB { red = 200; green = 150; blue = 100 };

global gray = GrayScale { lightness = 150; average = 150; luminosity = 150 };

int program (int argc, string[] argv) {
  var convert = rgbtogray(rgb);
  return (convert.average - gray.average) + (convert.lightness - gray.lightness);
}