用快读了，但是TLE了2个点

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define double long double

ll n,p,k,num[5000005];

ll read(){
    ll f=1,x=0;
    char ch;
    ch=getchar();
    while (ch>'9'||ch<'0'){
        if (ch=='-') f=-1;
        ch=getchar();
    }
    while (ch>='0'&&ch<='9'){
        x=10*x+(ch-'0');
        ch=getchar();
    }
    return x*f;
}

ll binpow(ll x,ll idx,ll mod){
    ll res=1;
    while(idx){
        if (idx&1) res=(res*x)%mod;
        x=(x*x)%mod;
        idx>>=1;
    }
    return res%mod;
}

int main(){
    n=read();
    p=read();
    k=read();
    for (ll i=1;i<=n;i++){
        ll t;
        t=read();
        ll x=binpow(t,p-2,p);
        num[i]=(x%p+p)%p;
    }
    ll ans=0;
    for (ll i=1;i<=n;i++){
        ll tmp;
        tmp=(binpow(k,i,p))*num[i];
        ans+=tmp%p;
    }
    printf("%lld",ans%p);
    return 0;
}