ludicrous "concatenation"

Index: src/cmd/script/script_statement.cpp
--- src/cmd/script/script_statement.cpp.orig
+++ src/cmd/script/script_statement.cpp
@@ -82,7 +82,7 @@ void Mission::doIf(missionNode *node, int mode) {
 
         int nr_subnodes = node->subnodes.size();
         if (nr_subnodes != 3) {
-            fatalError(node, mode, "an if-statement needs exact three subnodes, not " + nr_subnodes);
+            fatalError(node, mode, "an if-statement needs exactly three subnodes");
             printf("nr_of_subnodes: %d\n", nr_subnodes);
 
             assert(0);
