#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cstdlib>#include <cctype>#include <cmath>#include <vector>#include <map>#include <set>#include <string>#include <queue>#include <list>#include <stack>#include <bitset>#include <numeric>#include <functional>using namespace std;const int inf = 0x7fffffff;const int N = 105;const int mod = 1000000007;const double PI = acos(-1.0);const double eps = 1e-8;#define CC(a,b) memset(a,b,sizeof(a))template<class Z>inline bool checkmax(Z &a,Z b){if(a < b || a == -1) {a = b; return true;} return false;}template<class Z>inline bool checkmin(Z &a,Z b){if(a > b || a == -1) {a = b; return true;} return false;}template<class Z>inline Z ABS(Z a) {return a > 0 ? a : -a;}int cas = 0; void printcas() {printf("Case #%d: ", ++cas);}bool hash[N][N];int ans[N * N];int n;int idx;void DFS(int cur) {for(int i = 0; i < n; i++) {if(i != cur && !hash[cur][i]) {hash[cur][i] = hash[i][cur] = 1;DFS(i);}}ans[idx ++] = cur;}int main() {while(~scanf("%d", &n)) {CC(hash, 0);idx = 0;DFS(0);cout << idx - 1 << endl;for(int i = 1; i < idx - 1; i++)cout << ans[i] << " ";cout << ans[idx - 1] << endl;}return 0;}
