#scale N=int(input()) W=[int(i) for i in input().split()] S=0 for i in range(N): S+=W[i] if S%2==1: p="impossible" else: W.sort() S//=2 S-=W[-1] W.pop(-1) T=[0] U=[0] for i in range(N): T=U j=0 while Nd==0 and j <N: v=T[j]+W[i] if v==S: Nd=1 else: U.append(v) set(U) j+=1 if Nd==1: p="possible" else: p="impossible" print(p)