#include<cstdio>#include<vector>#include<algorithm>using namespace std; int main(){ bool b; int n,i,f; vector<int> v; while(scanf("%d",&n)!=EOF&&n) { while(n--) { scanf("%d",&i); v.push_back(i); } sort(v.begin(),v.end()); for(i=0,n=v.size()-1,b=false; i<n; ) { if(v[i]==v[i+1])i+=2; else { if(!b){ printf("%d",v[i]); ++i; b=true; } else { printf(" %d\n",v[i]); b=false; break; } } } if(b) printf(" %d\n",v[n]); v.clear(); } return 0;}/************************************************************** Problem: 1256 User: 3011216016 Language: C++ Result: Accepted Time:730 ms Memory:1024 kb****************************************************************/