a, b, k = map(int, input().split(' '))
ans = []
for i in range(1, 101):
    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, 101):
    if (a%i==0) and (b%i==0):
        ans.append(i) i range(1, 101) range 1 101 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 k = map(int, input().split(' ')) map(int, input().split(' ')) k ans = [] [] ans a, b, k = map(int, input().split(' ')) map(int, input().split(' ')) a
a, b, k = map(int, input().split(' '))
ans = []
for i in range(1, 101):
    if (a%i==0) and (b%i==0):
        ans.append(i)

print(ans[-k])