def match(N):
    result = 0
    if (N % 2 == 0):
        for i in range(N / 2):
            result  += 10**i
    else:
        for i in range(N/2):
            if(i == N/2 - 1):
                result += 7*10**i
            else:
                result  += 10**i

    return result