void printf(char*, ...);

int fibonacci(int n) {
    if (n < 2)
        return 1;
    return fibonacci(n - 1) + fibonacci(n - 2);
}

void modifyvalue(char* otus) {
    *otus = 20;
}

int main() {
    printf("10th fibonacci number is %d!", fibonacci(10));
    char res = 10;
    modifyvalue(&res);
    return res;
}