str = gets.split
N,M = str[0].to_i, str[1].to_i
r = Array.new(N+1){Array.new(0)}
o = Array.new(N+1,0)
a,b = 0,0
for x in 0...M do
    str = gets.split
    a,b = str[0].to_i, str[1].to_i
    r[a].push(b)
    r[b].push(a)
end
if M%2 != 0
    puts "-1"
    exit
end
s = Array.new(0)
for x in 1..N do
    s.push(x)
end
t = Array.new(0)
f = 0
n = 0
while s.size != 0
    t = s.dup
    f = 0
    while t.size != 0
        a = t.pop
        if r[a].size == 1
            f = 1
            s.delete(a)
            b = r[a].pop
            r[b].delete(a)
            if o[a]%2 == 0
                print b," ",a
                o[b] += 1
            else
                print a," ",b
                o[a] += 1
            end
            puts
            n += 1
            while r[b].size == 1
                a = b
                s.delete(a)
                b = r[a].pop
                r[b].delete(a)
                if o[a]%2 == 0
                    print b," ",a
                    o[b] += 1
                else
                    print a," ",b
                    o[a] += 1
                end
                puts
                n += 1
            end
        elsif r[a].size == 0
            s.delete(a)
        end
        if f == 0
            while r[a].size > 0
                b = r[a].pop
                r[b].delete(a)
                print b," ",a
                puts
                n += 1
                o[b] += 1
            end
            s.delete(a)
        end
        if n == N
            exit
        end
    end
end