a, b, c = map(int, input().split())

a -= c // 2
b -= c // 2

if ((a < 0) | (b < 0)):
    print(-1)
    exit(0)

if (a % 2) | (b % 2) :
    print(-1)
    exit(0)

for i in range(0, c // 2) : 
    print("10", end = '')


for i in range(0, a) :
    print("0", end = '')

for i in range(0, b) :
    print("1", end = '')