#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("inline")
#include<bits/stdc++.h>
using namespace std;
#define MD (998244353U)
template<class T> struct cLtraits_identity{
  using type = T;
}
;
template<class T> using cLtraits_try_make_signed =
  typename conditional<
    is_integral<T>::value,
    make_signed<T>,
    cLtraits_identity<T>
    >::type;
template <class S, class T> struct cLtraits_common_type{
  using tS = typename cLtraits_try_make_signed<S>::type;
  using tT = typename cLtraits_try_make_signed<T>::type;
  using type = typename common_type<tS,tT>::type;
}
;
void*wmem;
char memarr[96000000];
template<class S, class T> inline auto min_L(S a, T b)
-> typename cLtraits_common_type<S,T>::type{
  return (typename cLtraits_common_type<S,T>::type) a <= (typename cLtraits_common_type<S,T>::type) b ? a : b;
}
struct Rand{
  unsigned x;
  unsigned y;
  unsigned z;
  unsigned w;
  Rand(void){
    x=123456789;
    y=362436069;
    z=521288629;
    w=(unsigned)time(NULL);
  }
  Rand(unsigned seed){
    x=123456789;
    y=362436069;
    z=521288629;
    w=seed;
  }
  inline unsigned get(void){
    unsigned t;
    t = (x^(x<<11));
    x=y;
    y=z;
    z=w;
    w = (w^(w>>19))^(t^(t>>8));
    return w;
  }
  inline double getUni(void){
    return get()/4294967296.0;
  }
  inline int get(int a){
    return (int)(a*getUni());
  }
  inline int get(int a, int b){
    return a+(int)((b-a+1)*getUni());
  }
  inline long long get(long long a){
    return(long long)(a*getUni());
  }
  inline long long get(long long a, long long b){
    return a+(long long)((b-a+1)*getUni());
  }
  inline double get(double a, double b){
    return a+(b-a)*getUni();
  }
  inline int getExp(int a){
    return(int)(exp(getUni()*log(a+1.0))-1.0);
  }
  inline int getExp(int a, int b){
    return a+(int)(exp(getUni()*log((b-a+1)+1.0))-1.0);
  }
}
;
struct Modint{
  unsigned val;
  Modint(){
    val=0;
  }
  Modint(int a){
    val = ord(a);
  }
  Modint(unsigned a){
    val = ord(a);
  }
  Modint(long long a){
    val = ord(a);
  }
  Modint(unsigned long long a){
    val = ord(a);
  }
  inline unsigned ord(unsigned a){
    return a%MD;
  }
  inline unsigned ord(int a){
    a %= (int)MD;
    if(a < 0){
      a += MD;
    }
    return a;
  }
  inline unsigned ord(unsigned long long a){
    return a%MD;
  }
  inline unsigned ord(long long a){
    a %= (int)MD;
    if(a < 0){
      a += MD;
    }
    return a;
  }
  inline unsigned get(){
    return val;
  }
  inline Modint &operator++(){
    val++;
    if(val >= MD){
      val -= MD;
    }
    return *this;
  }
  inline Modint &operator--(){
    if(val == 0){
      val = MD - 1;
    }
    else{
      --val;
    }
    return *this;
  }
  inline Modint operator++(int a){
    Modint res(*this);
    val++;
    if(val >= MD){
      val -= MD;
    }
    return res;
  }
  inline Modint operator--(int a){
    Modint res(*this);
    if(val == 0){
      val = MD - 1;
    }
    else{
      --val;
    }
    return res;
  }
  inline Modint &operator+=(Modint a){
    val += a.val;
    if(val >= MD){
      val -= MD;
    }
    return *this;
  }
  inline Modint &operator-=(Modint a){
    if(val < a.val){
      val = val + MD - a.val;
    }
    else{
      val -= a.val;
    }
    return *this;
  }
  inline Modint &operator*=(Modint a){
    val = ((unsigned long long)val*a.val)%MD;
    return *this;
  }
  inline Modint &operator/=(Modint a){
    return *this *= a.inverse();
  }
  inline Modint operator+(Modint a){
    return Modint(*this)+=a;
  }
  inline Modint operator-(Modint a){
    return Modint(*this)-=a;
  }
  inline Modint operator*(Modint a){
    return Modint(*this)*=a;
  }
  inline Modint operator/(Modint a){
    return Modint(*this)/=a;
  }
  inline Modint operator+(int a){
    return Modint(*this)+=Modint(a);
  }
  inline Modint operator-(int a){
    return Modint(*this)-=Modint(a);
  }
  inline Modint operator*(int a){
    return Modint(*this)*=Modint(a);
  }
  inline Modint operator/(int a){
    return Modint(*this)/=Modint(a);
  }
  inline Modint operator+(long long a){
    return Modint(*this)+=Modint(a);
  }
  inline Modint operator-(long long a){
    return Modint(*this)-=Modint(a);
  }
  inline Modint operator*(long long a){
    return Modint(*this)*=Modint(a);
  }
  inline Modint operator/(long long a){
    return Modint(*this)/=Modint(a);
  }
  inline Modint operator-(void){
    Modint res;
    if(val){
      res.val=MD-val;
    }
    else{
      res.val=0;
    }
    return res;
  }
  inline operator bool(void){
    return val!=0;
  }
  inline operator int(void){
    return get();
  }
  inline operator long long(void){
    return get();
  }
  inline Modint inverse(){
    int a = val;
    int b = MD;
    int u = 1;
    int v = 0;
    int t;
    Modint res;
    while(b){
      t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    if(u < 0){
      u += MD;
    }
    res.val = u;
    return res;
  }
  inline Modint pw(unsigned long long b){
    Modint a(*this);
    Modint res;
    res.val = 1;
    while(b){
      if(b&1){
        res *= a;
      }
      b >>= 1;
      a *= a;
    }
    return res;
  }
  inline bool operator==(int a){
    return ord(a)==val;
  }
  inline bool operator!=(int a){
    return ord(a)!=val;
  }
}
;
inline Modint operator+(int a, Modint b){
  return Modint(a)+=b;
}
inline Modint operator-(int a, Modint b){
  return Modint(a)-=b;
}
inline Modint operator*(int a, Modint b){
  return Modint(a)*=b;
}
inline Modint operator/(int a, Modint b){
  return Modint(a)/=b;
}
inline Modint operator+(long long a, Modint b){
  return Modint(a)+=b;
}
inline Modint operator-(long long a, Modint b){
  return Modint(a)-=b;
}
inline Modint operator*(long long a, Modint b){
  return Modint(a)*=b;
}
inline Modint operator/(long long a, Modint b){
  return Modint(a)/=b;
}
inline int my_getchar_unlocked(){
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if(s == e && e == 1048576){
    e = fread_unlocked(buf, 1, 1048576, stdin);
    s = 0;
  }
  if(s == e){
    return EOF;
  }
  return buf[s++];
}
inline void rd(int &x){
  int k;
  int m=0;
  x=0;
  for(;;){
    k = my_getchar_unlocked();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = my_getchar_unlocked();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
inline void rd(Modint &x){
  int i;
  rd(i);
  x=i;
}
struct MY_WRITER{
  char buf[1048576];
  int s;
  int e;
  MY_WRITER(){
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER(){
    if(s){
      fwrite_unlocked(buf, 1, s, stdout);
    }
  }
}
;
MY_WRITER MY_WRITER_VAR;
void my_putchar_unlocked(int a){
  if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){
    fwrite_unlocked(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a){
  my_putchar_unlocked(a);
}
inline void wt_L(long long x){
  int s=0;
  int m=0;
  char f[20];
  if(x<0){
    m=1;
    x=-x;
  }
  while(x){
    f[s++]=x%10;
    x/=10;
  }
  if(!s){
    f[s++]=0;
  }
  if(m){
    my_putchar_unlocked('-');
  }
  while(s--){
    my_putchar_unlocked(f[s]+'0');
  }
}
template<class T> struct Matrix{
  int r;
  int c;
  int mem;
  T*dat;
  Matrix(){
    r=c=mem = 0;
  }
  Matrix(const int rr, const int cc){
    if(rr == 0 || cc == 0){
      r = c = 0;
    }
    else{
      r = rr;
      c = cc;
    }
    mem = r * c;
    if(mem > 0){
      dat = new T[mem];
    }
  }
  Matrix(const Matrix<T> &a){
    int i;
    r = a.r;
    c = a.c;
    mem = r * c;
    dat = new T[mem];
    for(i=(0);i<(mem);i++){
      dat[i] = a.dat[i];
    }
  }
  ~Matrix(){
    if(mem){
      delete [] dat;
    }
  }
  void changeSize(const int rr, const int cc){
    if(rr==0 || cc==0){
      r = c = 0;
    }
    else{
      r = rr;
      c = cc;
    }
    if(mem < r*c){
      if(mem){
        delete [] dat;
      }
      mem = r*c;
      dat = new T[mem];
    }
  }
  Matrix<T>& operator=(const Matrix<T> &a){
    int i;
    int j;
    r = a.r;
    c = a.c;
    j = r * c;
    changeSize(r,c);
    for(i=(0);i<(j);i++){
      dat[i] = a.dat[i];
    }
    return *this;
  }
  Matrix<T>& operator=(const int a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] = 0;
    }
    j =min_L(r, c);
    for(i=(0);i<(j);i++){
      dat[i*c+i] = a;
    }
    return *this;
  }
  Matrix<T>& operator+=(const Matrix<T> &a){
    int i;
    int j;
    if(r==0 || r!=a.r || c!=a.c){
      changeSize(0,0);
      return *this;
    }
    j = r*c;
    for(i=(0);i<(j);i++){
      dat[i] += a.dat[i];
    }
    return *this;
  }
  Matrix<T> operator+(const Matrix<T> &a){
    return Matrix<T>(*this) += a;
  }
  Matrix<T>& operator-=(const Matrix<T> &a){
    int i;
    int j;
    if(r==0 || r!=a.r || c!=a.c){
      changeSize(0,0);
      return *this;
    }
    j = r*c;
    for(i=(0);i<(j);i++){
      dat[i] -= a.dat[i];
    }
    return *this;
  }
  Matrix<T> operator-(const Matrix<T> &a){
    return Matrix<T>(*this) -= a;
  }
  Matrix<T>& operator*=(const Matrix<T> &a){
    int i;
    int j;
    int k;
    int x;
    T*m;
    if(r==0 || c!=a.r){
      changeSize(0,0);
      return *this;
    }
    m = (T*)wmem;
    x = r * a.c;
    for(i=(0);i<(x);i++){
      m[i] = 0;
    }
    for(i=(0);i<(r);i++){
      for(k=(0);k<(c);k++){
        for(j=(0);j<(a.c);j++){
          m[i*a.c+j] += dat[i*c+k] * a.dat[k*a.c+j];
        }
      }
    }
    changeSize(r, a.c);
    for(i=(0);i<(x);i++){
      dat[i] = m[i];
    }
    return *this;
  }
  Matrix<T> operator*(const Matrix<T> &a){
    return Matrix<T>(*this) *= a;
  }
  Matrix<T>& operator*=(const int a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  Matrix<T>& operator*=(const long long a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  Matrix<T>& operator*=(const double a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  inline T* operator[](const int a){
    return dat+a*c;
  }
}
;
template<class T> Matrix<T> operator*(const int a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const int a){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const long long a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const long long a){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const double a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const double a){
  return Matrix<T>(b)*=a;
}
template<class T, class S> inline Matrix<T> pow_L(Matrix<T> a, S b){
  int i;
  int j;
  Matrix<T> res;
  res.changeSize(a.r, a.c);
  res = 1;
  while(b){
    if(b&1){
      res *= a;
    }
    b >>= 1;
    a *= a;
  }
  return res;
}
template<class T, class S> inline T pow_L(T a, S b){
  T res = 1;
  res = 1;
  for(;;){
    if(b&1){
      res *= a;
    }
    b >>= 1;
    if(b==0){
      break;
    }
    a *= a;
  }
  return res;
}
inline double pow_L(double a, double b){
  return pow(a,b);
}
unsigned long long HashMap_ullP_L[4];
template<class KEY, class VAL> struct HashMap{
  char*used;
  KEY*key;
  VAL*val;
  int mem;
  int n;
  int mask;
  int init_flag;
  VAL init_val;
  HashMap(){
    mem = 0;
    init_flag = 0;
  }
  ~HashMap(){
    free();
  }
  void expand(int nn){
    if(mem >= nn){
      return;
    }
    if(mem){
      free();
    }
    mem = nn;
    used = new char[nn];
    key = new KEY[nn];
    val = new VAL[nn];
  }
  void free(){
    if(mem){
      mem = 0;
      delete[] used;
      delete[] key;
      delete[] val;
    }
  }
  void init(int nn){
    int i;
    n = 1;
    nn = nn + (nn + 1) / 2;
    while(n < nn){
      n *= 2;
    }
    mask = n - 1;
    expand(n);
    for(i=(0);i<(n);i++){
      used[i] = 0;
    }
    init_flag = 0;
  }
  void init(int nn, VAL ini){
    int i;
    n = 1;
    nn = nn + (nn + 1) / 2;
    while(n < nn){
      n *= 2;
    }
    mask = n - 1;
    expand(n);
    for(i=(0);i<(n);i++){
      used[i] = 0;
    }
    init_flag = 1;
    init_val = ini;
  }
  inline int getHash(const int a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const unsigned a){
    unsigned long long d = a;
    d = (((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) & mask;
    return d;
  }
  inline int getHash(const long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const unsigned long long a){
    unsigned long long d = a;
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline int getHash(const pair<int,int> a){
    unsigned long long d = (((unsigned long long)a.first) << 32) + ((unsigned long long)a.second);
    d = (((((d * HashMap_ullP_L[0]) >> 32) * HashMap_ullP_L[1]) >> 32) * HashMap_ullP_L[2]) & mask;
    return d;
  }
  inline VAL& operator[](const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        break;
      }
      if(used[k]==0){
        used[k] = 1;
        key[k] = a;
        if(init_flag){
          val[k] = init_val;
        }
        break;
      }
      k = (k+1) & mask;
    }
    return val[k];
  }
  inline bool exist(const KEY a){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
  template<class S> inline bool exist(const KEY a, S &res){
    int k = getHash(a);
    for(;;){
      if(used[k]==1 && key[k]==a){
        res = val[k];
        return true;
      }
      if(used[k]==0){
        break;
      }
      k = (k+1) & mask;
    }
    return false;
  }
}
;
int main(){
  wmem = memarr;
  {
    int i;
    int j;
    int k;
    Rand rnd;
    for(i=(0);i<(20);i++){
      rnd.get(2);
    }
    for(i=(0);i<(4);i++){
      for(j=(0);j<(32);j++){
        k = rnd.get(1,62);
        HashMap_ullP_L[i] |= (1ULL << k);
      }
      HashMap_ullP_L[i] |= (1ULL << 0);
      HashMap_ullP_L[i] |= (1ULL << 63);
    }
  }
  long long i;
  long long res;
  Modint A;
  rd(A);
  Modint B;
  rd(B);
  Modint P;
  rd(P);
  Modint Q;
  rd(Q);
  Modint x;
  Modint y;
  Modint t;
  Matrix<Modint> mt(2,2);
  Matrix<Modint> pw;
  HashMap<pair<int,int>,int> hs;
  hs.init(100000);
  for(i=(0);i<(100000);i++){
    hs[{P,Q}] = i;
    if(B==0){
      t = Q / A;
    }
    else{
      t = (A*Q - P) / B;
    }
    auto Q5VJL1cS = ((Q));
    auto e98WHCEY = (( t));
    P=Q5VJL1cS;
    Q=e98WHCEY;
  }
  mt = 0;
  mt[0][0] = A;
  mt[0][1] = -B;
  mt[1][0] = 1;
  for(i=0;;i++){
    pw =(pow_L(mt,(i * 100000)));
    x = pw[0][0] * A + pw[0][1] * 2;
    y = pw[1][0] * A + pw[1][1] * 2;
    if(hs.exist({x,y})){
      res = i * 100000 + hs[{x,y}] + 1;
      wt_L(res);
      wt_L('\n');
      break;
    }
  }
  return 0;
}
// cLay version 20210717-1 [beta]

// --- original code ---
// #define MD 998244353
// {
//   ll i, res;
//   Modint @A, @B, @P, @Q, x, y, t;
//   Matrix<Modint> mt(2,2), pw;
//   HashMap<pair<int,int>,int> hs;
//   hs.init(1d5);
// 
//   rep(i,1d5){
//     hs[{P,Q}] = i;
//     if(B==0) t = Q / A;
//     else     t = (A*Q - P) / B;
//     (P, Q) = (Q, t);
//   }
// 
//   mt = 0;
//   mt[0][0] = A;
//   mt[0][1] = -B;
//   mt[1][0] = 1;
// 
//   for(i=0;;i++){
//     pw = mt ** (i * 1d5);
//     x = pw[0][0] * A + pw[0][1] * 2;
//     y = pw[1][0] * A + pw[1][1] * 2;
//     if(hs.exist({x,y})){
//       res = i * 1d5 + hs[{x,y}] + 1;
//       wt(res);
//       break;
//     }
//   }
// 
// }