#include <bits/stdc++.h>
inline void cmin(int &a, int b) {
  if (b < a) a = b;
}
int a[1000005], f[1 << 21];
int main() {
  int n, i, now, ans, l, j, k;
  char s[22];
  for (scanf("%d", &n), i = 0; i < n; i++) {
    scanf("%s", s);
    for (a[i] = j = 0; s[j]; j++) a[i] = (a[i] << 1) + s[j] - '0';
  }
  memset(f, 1, sizeof f);
  for (f[0] = 0, ans = l = strlen(s), i = 1; i < n; i++) {
    for (k = 0; (a[i - 1] & (1 << l - k) - 1) != (a[i] >> k); k++)
      ;
    ans += k;
    for (now = 1 << 25, j = 0; j <= l; j++)
      cmin(now, f[(1 << l - j) - 1 + (a[i] >> j)] + j);
    for (now -= k, j = 0; j <= l; j++)
      cmin(f[(1 << j) - 1 + (a[i - 1] & (1 << j) - 1)], now);
  }
  for (now = i = 0; i < 1 << 21; i++) cmin(now, f[i]);
  printf("%d\n", ans + now);
  return 0;
}
