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