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