#include <bits/stdc++.h>
using namespace std;
const array<int, 11> MODS = {3960, 960, 256, 128, 64, 32, 16, 8, 4, 2, 1};
int modulo(int a, int m){
  if (a < m){
    return a;
  } else {
    return a % m + m;
  }
}
int modpow(int a, int b, int m){
  int ans = 1;
  while (b > 0){
    if (b % 2 == 1){
      ans = modulo(ans * a, m);
      ans %= m;
    }
    a = modulo(a * a, m);
    b /= 2;
  }
  return ans;
}
array<int, 11> modpow(array<int, 11> a, array<int, 11> b){
  array<int, 11> c;
  for (int i = 0; i < 10; i++){
    c[i] = modpow(a[i], b[i + 1], MODS[i]);
  }
  if (a[0] == 0 && b[0] > 0){
    c[10] = 0;
  } else {
    c[10] = 1;
  }
  return c;
}
array<int, 11> get(long long x){
  array<int, 11> A;
  for (int i = 0; i < 11; i++){
    A[i] = modulo(x, MODS[i]);
  }
  return A;
}
array<int, 11> operator +(array<int, 11> A, array<int, 11> B){
  array<int, 11> C;
  for (int i = 0; i < 11; i++){
    C[i] = modulo(A[i] + B[i], MODS[i]);
  }
  return C;
}
int main(){
  long long M;
  cin >> M;
  long long D;
  cin >> D;
  long long N;
  cin >> N;
  int B;
  cin >> B;
  if (M == 0 && D == 0){
    if (N % 2 == 0){
      cout << 0 << endl;
    } else {
      cout << 1 << endl;
    }
  } else {
    array<int, 11> m = get(M);
    array<int, 11> d = get(D);
    map<array<int, 11>, int> mp;
    mp[m] = 0;
    vector<array<int, 11>> h = {m};
    int t = 0;
    int ans;
    while (true){
      if (t == N){
        ans = m[0] % B;
        break;
      }
      t++;
      m = modpow(m + d, m);
      h.push_back(m);
      if (mp.count(m) == 1){
        int t2 = mp[m];
        int p = (N - t2) % (t - t2) + t2;
        ans = h[p][0] % B;
        break;
      }
      mp[m] = t;
    }
    if (ans < 10){
      cout << ans << endl;
    } else {
      cout << 'A' << endl;
    }
  }
}