#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} #define MAXN 1010 int a[MAXN],b[MAXN]; int N; int main() { while (scanf("%d",&N)!=EOF) { if (N == 0) break ; for (int i = 1; i <= N; i++) scanf("%d", &a[i]),a[i+N] = a[i]; int ans = INT_MAX; for (int i = 1; i <= N; i++) { int tmp = 0; memcpy(b,a,sizeof(a)); for (int j = 1; j <= N; j++) { int x = i + j - 1; if (b[x] != j) { tmp ++; int t = b[x]; b[x] = j; for (int k = x + 1; k < i + N ; k++) if (b[k] == j) { b[k] = t; break; } } } ans = min (ans, tmp); tmp = 0 ; memcpy(b,a,sizeof(a)); for (int j = N; j >= 1 && tmp < ans; j--) { int x = i + N - j; if (b[x] != j) { tmp ++ ; int t = b[x]; b[x] = j; for (int k = x + 1; k < i + N; k++) if (b[k] == j) { b[k] = t; break; } } } ans = min (ans,tmp); } printf("%d ",ans); } return 0; }