#include using namespace std; #define REP(i, n) for(int i=0; i<(n); ++i) #define RREP(i, n) for(int i=(n);i>=0;--i) #define FOR(i, a, n) for (int i=(a); i<(n); ++i) #define RFOR(i, a, b) for(int i=(a);i>=(b);--i) #define SZ(x) ((int)(x).size()) #define ALL(x) (x).begin(),(x).end() #define DUMP(x) cerr<<#x<<" = "<<(x)< ostream &operator<<(ostream &os, const vector &v) { REP(i, SZ(v)) { if (i) os << " "; os << v[i]; } return os; } template void debug(const vector &v) { cout << "["; REP(i, SZ(v)) { if(i) cout << ", "; cout << v[i]; } cout << "]" << endl; } template ostream &operator<<(ostream &os, const pair &p) { return os << p.first << " " << p.second; } template void debug(const pair &p) { cout << "(" << p.first << " " << p.second << ")" << endl; } template bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; } using ll = long long; using ull = unsigned long long; using ld = long double; using P = pair; using vi = vector; using vll = vector; using vvi = vector; using vvll = vector; const ll MOD = 1e9 + 7; const ll MOD998 = 998244353; const int INF = INT_MAX; const ll LINF = LLONG_MAX; const int inf = INT_MIN; const ll linf = LLONG_MIN; const ld eps = 1e-9; template struct mint { int x; mint(ll x = 0) : x(((x % m) + m) % m) {} mint operator-() const { return x ? m - x : 0; } mint &operator+=(mint r) { if ((x += r.x) >= m) x -= m; return *this; } mint &operator-=(mint r) { if ((x -= r.x) < 0) x += m; return *this; } mint &operator*=(mint r) { x = ((ll) x * r.x) % m; return *this; } mint inv() const { return pow(m - 2); } mint &operator/=(mint r) { return *this *= r.inv(); } friend mint operator+(mint l, mint r) { return l += r; } friend mint operator-(mint l, mint r) { return l -= r; } friend mint operator*(mint l, mint r) { return l *= r; } friend mint operator/(mint l, mint r) { return l /= r; } mint pow(ll n) const { mint ret = 1, tmp = *this; while (n) { if (n & 1) ret *= tmp; tmp *= tmp, n >>= 1; } return ret; } friend bool operator==(mint l, mint r) { return l.x == r.x; } friend bool operator!=(mint l, mint r) { return l.x != r.x; } friend ostream &operator<<(ostream &os, mint a) { return os << a.x; } friend istream &operator>>(istream &is, mint &a) { ll x; is >> x; a = x; return is; } }; using Int = mint; int main() { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(10); int n, m, p; cin >> n >> m >> p; vector> v; int ma = 0; REP(i, n) { int a; cin >> a; chmax(ma, a); int cnt = 1; while(a % p == 0) { a /= p; cnt++; } v.emplace_back(a, cnt); } int ans = INF; if(ma >= m) ans = 1; REP(i, n) { ll now = 1; int cnt = 1; if(v[i].first == 1) continue; while(now * ma < m) { now *= v[i].first; cnt += v[i].second; } chmin(ans, cnt); } cout << (ans == INF ? -1 : ans) << endl; return 0; }