from math import lcm

XY = [tuple(map(int, input().split())) for _ in range(3)]

rem, mod = XY[0]

ans = -1
for rem_, mod_ in XY[1:]:
    for i in range(mod_):
        if (mod * i + rem) % mod_ == rem_:
            rem = mod * i + rem
            mod = lcm(mod, mod_)
            rem %= mod
            break
    else:
        break
else:
    ans = (rem-1)%mod+1
print(ans)