s=[2,3]

for i in range(20000):
    s.append(6*i+5)
    s.append(6*i+7)

la=len(s)

for j in range(2,10000):
    i=j+1
    while i<la:
        if s[i]%s[j]==0:
            x=s.pop(i)
            i+=-1
            la+=-1
        i+=1
print(s[10000])