#include <bits/stdc++.h>
using namespace std;
//https://trap.jp/post/1444/
constexpr uint32_t totient(uint32_t x){
    uint32_t ans = x;
    for(uint32_t i = 2; i * i <= x; i++) if(x % i == 0){
        ans /= i;
        ans *= i - 1;
        do x /= i; while(x % i == 0);
    }
    if(x != 1){
        ans /= x;
        ans *= x - 1;
    }
    return ans;
}
template<uint32_t P> struct Modint{
    static_assert(P < 0x80000000, "P must be smaller than 2^31");
    uint32_t a;
    Modint<totient(P)> b;
private:
    static uint32_t mod(uint64_t x){
        if(x < P * 2) return uint32_t(x);
        return uint32_t(x % P) + P;
    }
    static uint32_t mul(uint32_t a, uint32_t b){
        return mod(uint64_t(a) * b);
    }
    static uint32_t pow(uint32_t a, uint32_t b){
        uint32_t ans = 1;
        while(b){
            if(b & 1) ans = mul(ans, a);
            a = mul(a, a);
            b >>= 1;
        }
        return ans;
    }
public:
    Modint(uint64_t x): a(mod(x)), b(x){}
    Modint(uint32_t a, Modint<totient(P)> b): a(a), b(b){}
    uint32_t val() const {
        if(a < P) return a;
        return a - P;
    }
    Modint& operator*=(const Modint& other){
        a = mul(a, other.a);
        b *= other.b;
        return *this;
    }
    Modint operator*(const Modint& other) const {
        return Modint(*this) *= other;
    }
    Modint& operator+=(const Modint& other){
        a += other.a;
        if(a >= P * 2) a -= P;
        if(a >= P * 2) a -= P;
        b += other.b;
        return *this;
    }
    Modint operator+(const Modint& other) const {
        return Modint(*this) += other;
    }
    Modint pow(const Modint& other) const {
        return {pow(a, other.b.a), b.pow(other.b)};
    }
    bool operator==(const Modint& other) const {
        return a == other.a && b == other.b;
    }
};
template<> struct Modint<1>{
    uint32_t a;
    Modint(uint64_t x): a(bool(x)){}
    uint32_t val() const {
        return 0;
    }
    Modint& operator*=(const Modint& other){
        a &= other.a;
        return *this;
    }
    Modint operator*(const Modint& other) const {
        return Modint(*this) *= other;
    }
    Modint& operator+=(const Modint& other){
        a |= other.a;
        return *this;
    }
    Modint operator+(const Modint& other) const {
        return Modint(*this) += other;
    }
    Modint pow(const Modint& other) const {
        return {a || !other.a};
    }
    bool operator==(const Modint& other) const {
        return a == other.a;
    }
};
int main(){
  long long M;
  cin >> M;
  long long D;
  cin >> D;
  long long N;
  cin >> N;
  int B;
  cin >> B;
  assert(3960 % B == 0);
  Modint<3960> m(M), d(D);
  vector<Modint<3960>> C;
  C.push_back(m);
  int t1, t2;
  while (true){
    m = (m + d).pow(m);
    int cnt = C.size();
    bool ok = false;
    for (int i = 0; i < cnt; i++){
      if (C[i] == m){
        t1 = i;
        t2 = C.size();
        ok = true;
      }
    }
    C.push_back(m);
    if (ok){
      break;
    }
  }
  int ans;
  if (N <= t2){
    ans = C[N].val() % B;
  } else {
    ans = C[(N - t1) % (t2 - t1) + t1].val() % B;
  }
  if (ans < 10){
    cout << ans << endl;
  } else {
    cout << 'A' << endl;
  }
}