int silnia(int n) {
if(n == 0) return 1;
else return n * silnia(n-1);
}
int binary_search(int *tab, int x, int left, int right) {
if(left == right)
if(tab[left] == x) return left;
else return -1;
else {
int mid = (left + right)/2;
if(tab[mid] == x) return mid;
else
if (x < tab[mid]) return binary_search(tab, x, left, mid);
else return binary_search(tab, x, left, right);
}
}