#include <cstdio>int t,n,a[10];int main(){    while(~scanf("%d",&n)){        int flag=0;        for(int i=0;i<10;i++)a[i]=0;        for(int i=0;i<n;i++)scanf("%d",&t),a[t]++;        if(n==1){printf("%d\n",t&1?t:-1);continue;}        for(int i=1;i<10;i+=2)if(a[i]){flag=1;a[i]--;t=i;break;}        if(flag==0){puts("-1");continue;}flag=0;        for(int i=1;i<10;i++)if(a[i]>0)flag=1;        if(flag==0){puts("-1");continue;}        for(int i=9;i>=0;i--)while(a[i]>0)printf("%d",i),a[i]--;        printf("%d\n",t);    }return 0;}//注意n==1的情况

HDU 5055 Bob and math problem