a, b, k = map(int, input().split())
ans = []
for i in range(1, 100+1):
    if a % i == 0 and b % i == 0:
        ans.append(i)
print(ans[-k]) a, b, k = map(int, input().split()) a map(int, input().split()) map int input().split() ().split () input split b k ans = [] ans [] for i in range(1, 100+1):
    if a % i == 0 and b % i == 0:
        ans.append(i) i range(1, 100+1) range 1 100+1 100 1 if a % i == 0 and b % i == 0:
        ans.append(i) a % i == 0 and b % i == 0 a % i == 0 a % i a i 0 b % i == 0 b % i b i 0 ans.append(i) ans.append ans append i print(ans[-k]) print ans[-k] ans -k k b, k = map(int, input().split()) map(int, input().split()) b a, b, k = map(int, input().split()) map(int, input().split()) a ans = [] [] ans k = map(int, input().split()) map(int, input().split()) k
a, b, k = map(int, input().split())
ans = []
for i in range(1, 100+1):
    if a % i == 0 and b % i == 0:
        ans.append(i)
print(ans[-k])