diff --git a/enumerate.c b/enumerate.c
index fd14cca..17243fc 100644
--- a/enumerate.c
+++ b/enumerate.c
@@ -228,7 +228,7 @@ int main(int argc, const char *argv[])
   for(int i = 0; i < type.n; i++) {
     type.factors[i].series = argv[i+1][0];
     type.factors[i].rank = argv[i+1][1] - '0';
-    ERROR(argv[i+1][0] < 'A' || argv[i+1][0] > 'I' || argv[i+1][1] < '1' || argv[i+1][1] > '9', "Arguments must be Xn with X out of A-G and n out of 1-9\n");
+    ERROR(argv[i+1][0] < 'A' || argv[i+1][0] > 'G' || argv[i+1][1] < '1' || argv[i+1][1] > '9', "Arguments must be Xn with X out of A-G and n out of 1-9\n");
   }
 
   left_invariance = right_invariance = 0;