Let P be the number of pages of the first issue of the comic.
The second issue is the same number of pages, so the first and second issues are P + P = 2P pages.
The third issue is 4 pages longer, so it is P + 4 pages.
All three issues are 2P + P + 4 = 3P + 4 = 220 pages long.
Thus, 3P = 220 - 4 = 216 pages.
Therefore, the first issue of the comic was P = 216 / 3 = <<216/3=72>>72 pages.
#### 72