// #include<stdio.h>

#define SIZE 5

// Searching for the value below
#define TO_FIND 57

char search (char tab[], char size, char to_find) {
  char low = 0, high = size-1, i;

  while (high >= low) {
    i = (high+low) / 2;
    if (tab[i] == to_find) return i;
    if (tab[i] > to_find) high = i-1;
    if (tab[i] < to_find) low = i+1;
  }

  return (-1);
}

int main () {
  char tab[SIZE] = {0, 18, 23, 57, 120};
  char res = search(tab, SIZE, TO_FIND);

  //  printf("%d\n", res);
  return res;
}