#include <bits/stdc++.h>



using namespace std;
int n,x,y,S=0;
vector<int>G[100001];
int max0=0,sol[1001],v[1001];
int main(){
    cin>>n>>x>>y;
    for(int i=1;i<=n;i++){
        cin>>v[i]; S+=v[i];
        G[v[i]].push_back(i);
    }
    for(int i=1;i<=n;i++){
        int val =  1 + (x * i + y * v[i]);
        val%=n;
        /// toate elementele de la i+1 care au v[i]
        /// sunt schimbate in val
        while(!G[val].empty()){
            int poz = G[val].back();
            if(poz<=i)
                break;
        }
    }
    cout<<max0;
    return 0;
}