#!/usr/bin/env python
# -*- coding: utf-8 -*-

N = 3
X = []
Y = []
max_x,max_y = 0,0
for i in range(N):
    x,y = map(int,input().split())
    X.append(x)
    Y.append(y)
    if max_y < y:
        max_y = y
        max_x = x

# max_x + n*max_yの周期中に答えがあるはず
for i in range(max_x,10**6,max_y):
    for j in range(N):
        if i%Y[j] != X[j]:
            break
    else:
        break
else:
    print(-1)
    quit()
print(i)