// yukicoder: No.4 おもりと天秤 // 2019.4.7 bal4u // dp #include int w[102]; int N; char dp[10205]; int check(int goal) { int i, j; dp[0] = 1; for (i = 0; i < N; i++) { for (j = 0; j < goal; j++) if (dp[j]) dp[j + w[i]] = 1; } return dp[goal] == 1; } int main() { int i, goal; char *msg[] = { "impossible", "possible" }; scanf("%d", &N); goal = 0; for (i = 0; i < N; i++) scanf("%d", w + i), goal += w[i]; if (goal & 1) puts(msg[0]); else puts(msg[check(goal >> 1)]); return 0; }