f0(x) { return (x, x); }
f1(x) { return f0(f0(x)); }
-// f2(x) { return f1(f1(x)); }
-// f3(x) { return f2(f2(x)); }
-// f4(x) { return f3(f3(x)); }
+f2(x) { return f1(f1(x)); }
+f3(x) { return f2(f2(x)); }
+//f4(x) { return f3(f3(x)); } //using f4 gives Heap-full
// f5(x) { return f4(f4(x)); }
+main() {return;}
\ No newline at end of file