a,b,c = map(int,input().split())
ans = set([])
if(c % a == 0):
    ans.add(c // a)
if((c + b) % a == 0):
    ans.add((c + b) // a)
    
flag = True
for k in sorted(ans):
    x = k * a
    if(x - b > 0):
        x -= b
    if(x != c):
        continue
    print(k)
    flag = False
if(flag):
	print(-1)