#!/usr/bin/env python

num = int(raw_input())
sigma = 0
shou = num / 2
if num % 2 == 0:
    for i in range(shou):
        sigma += 10**i
else:
    sigma += 7 * (10**(shou-1))
    for i in range(shou-1):
        sigma += 10**i
print(sigma)