#include<bits/stdc++.h>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
#define mypc(c) putchar_unlocked(c)

void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void writer(const char c[]){int i;for(i=0;c[i]!='\0';i++)mypc(c[i]);}

int dp[11000];

int main(){
  int i, j, k;
  int N, W, sum;

  reader(&N);
  sum = 0;
  dp[0] = 1;
  while(N--){
    reader(&W);
    sum += W;
    for(i=10000;i>=0;i--) if(dp[i]) dp[i+W] = 1;
  }
  if(sum%2==0&&dp[sum/2]) writer("possible\n"); else writer("impossible\n");

  return 0;
}