a = int(input())
num = 0
if a%2 == 0:
    b =int(a/2)
    for i in range(0,b):
        c =10**i
        num += c
    print(num)
else:
    b =int(a/2)
    for i in range(0,b-1):
        c =10**i
        num += c
    d = num + 10**(b-1)*7
    print(d)