#include <stdio.h>

#define NMAX	(100)
#define WMAX	(100)

int main(void){
	int ans = 1;
	int i,j,n;
	
	int wSum = 0;
	int weight[NMAX+10];
	char dp[NMAX+10][(WMAX*WMAX)/2+100];
	
	for(i=0;i<NMAX+10;i++){
		for(j=0;j<WMAX/2+100;j++){
			dp[i][j] = 0;
		}
	}
	dp[0][0] = 1;
	
	scanf("%d", &n);
	
	for(i=0;i<n;i++){
		scanf("%d", &weight[i]);
		wSum = wSum + weight[i];
	}
	
	if(wSum%2 == 0){
		for(i=1;i<=n;i++){
			int w = weight[i-1];
			for(j=0;j<=(wSum/2+10);j++){
				if(dp[i-1][j] == 1){
					int tsum = j + w;
					dp[i][j] = 1;
					if(tsum <= (wSum/2+10)){
						dp[i][tsum] = 1;
					}
				}
			}
		}
		
		if(dp[n][wSum/2] != 1){
			ans = 0;
		}
		
	}else{
		ans = 0;
	}
	
	if(ans == 1){
		printf("possible\n");
	}else{
		printf("impossible\n");
	}
	return 0;
}