M = 2*10**5
prime = [0]*M
cand = []
for i in range(2,M):
    if prime[i]:
        continue
    if i > 10**5:
        cand.append(i)
    for j in range(i,M,i):
        prime[j] = 1


n = int(input())
cand = cand[:20]

ans = [1]
for c in cand:
    for c in cand:
        ans.append(c*c)

ans = sorted(set(ans))

print(ans[n-1])