def is_prime(num): if num==1: return False if num==2: return True for i in range(2,int(num**0.5)+1): if num%i==0: return False return True def prime_pairs(n): primes=[] for i in range(1,n+1): if is_prime(i): primes.append(i) pairs=[] for i in range(len(primes)-1): if primes[i]+2==primes[i+1]: pairs.append((primes[i],primes[i+1])) return pairs n=int(input()) pairs=prime_pairs(n) if pairs: for pair in pairs: print(*pair) else: print("No")