#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;

vi X, Y;

void init(){
  X = Y = vi( 3 );
  for( int i = 0; i < 3; ++i ){
    cin >> X[ i ] >> Y[ i ];
  }
}

void preprocess(){
  int a = -1;
  for( int i = 0; i <= Y[ 1 ]; ++i ){
    a = X[ 0 ] + Y[ 0 ] * i;
    if( a % Y[ 1 ] == X[ 1 ] ){
       break;
    }
    a = -1;
  }
  if( a == -1 ){
    cout << -1 << endl;
    exit( 0 );
  }
  int lcm_y01 = Y[ 0 ] / __gcd( Y[ 0 ], Y[ 1 ] ) * Y[ 1 ];
  int b = -1;
  for( int i = 0; i <= Y[ 2 ]; ++i ){
    b = a + lcm_y01 * i;
    if( b == 0 ){
      b = -1;
      continue;
    }
    if( b % Y[ 2 ] == X[ 2 ] ){
      break;
    }
    b = -1;
  }
  if( b == -1 ){
    cout << -1 << endl;
    exit( 0 );
  }
  cout << b << endl;
}

void solve(){

}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}