uint64_t fibonacci(uint64_t n) { if (n <= 1) return n; else return fibonacci(n - 1) + fibonacci(n - 2); } uint64_t main() { uint64_t a; uint64_t* x; x = malloc(sizeof(uint64_t)); *x = 0; // touch memory read(0, x, 1); *x = *x - 46; // 2 == fibonacci(3) a = fibonacci(*x); if (a == 2) // non-zero exit code if the input is '1' (== 49 == b00110001) return 1; else return 0; }