#include<cstdio>#include<cstring>#include<algorithm>using namespace std;int n,go[200][200];bool vis[200];bool check(int a,int b,int &sa){ bool flag=true; for(int i=0;i<n;i++) { if(!vis[i]&&i!=a&&i!=b) { if(flag) { sa=go[a][i]-(go[a][i]+go[b][i]-go[a][b])/2; flag=false; } else if(sa!=go[a][i]-(go[a][i]+go[b][i]-go[a][b])/2) return false; } } return true;}int main(){ //freopen("data.txt","r",stdin); while(scanf("%d",&n),n) { memset(vis,false,sizeof(vis)); for(int i=0;i<n;i++) { go[i][i]=0; for(int j=i+1;j<n;j++) scanf("%d",&go[i][j]),go[j][i]=go[i][j]; } int ans=0,sa,a,b; while(1) { bool flag=false; for(a=0;a<n;a++) { if(vis[a]) continue; for(b=a+1;b<n;b++) { if(vis[b]) continue; if(check(a,b,sa)) { flag=true; break; } } if(flag) break; } if(!flag) break; ans+=go[a][b]; vis[a]=vis[b]=true; for(int j=0;j<n;j++) { if(!vis[j]) go[j][n]=go[n][j]=go[j][a]-sa; } n++; } printf("%dn",ans); } return 0;}
