#include using namespace std; #define REP(i,a,n) for(int i=(a); i<(int)(n); i++) #define rep(i,n) REP(i,0,n) #define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it) #define ALLOF(c) (c).begin(), (c).end() typedef long long ll; typedef unsigned long long ull; int main(){ ll N, M, P; cin >> N >> M >> P; vector v(N); rep(i,N){ cin >> v[i]; } ll ret = 1e18; rep(i,N){ if(v[i] % P == 0) continue; ll x = 1; ll cnt = 0; while(x <= M){ cnt++; x *= v[i]; } ret = min(ret, cnt); } if(ret == 1e18) cout << -1 << endl; else cout << ret << endl; return 0; }