#include<cstdio>

#define sid 1000500

#define ri register int

#define ll long long

#define dd double

using namespace std;

#define getchar() *S ++

char RR[], *S = RR;

inline int read(){

    int p = , w = ;

    char c = getchar();

    while(c > '' || c < '') {

        if(c == '-') w = -;

        c =  getchar();

    }

    while(c >= '' && c <= '') {

        p = p *  + c - '';

        c = getchar();

    }

    return p * w;

}

ll dp[sid], sum[sid];

int q[sid], n, a, b, c;

#define x(g) (sum[(g)])

#define y(g) (dp[(g)] + a * sum[(g)] * sum[(g)] - b * sum[(g)])

inline dd s(int i,int j){

    return (dd)(y(i) - y(j)) / (dd)(x(i) - x(j));

}

int main(){

    fread(RR, , sizeof(RR), stdin);

    n = read(); a = read();

    b = read(); c = read();

    for(ri i = ; i <= n; i ++) sum[i] = sum[i - ] + read();

    ri fr = , to = ;

    for(ri i = ; i <= n; i ++){

        while(fr +  <= to && s(q[fr],q[fr + ]) >  * a * sum[i]) fr ++;

        int p = q[fr];

        ll pp = sum[i] - sum[p];

        dp[i] = dp[p] + a * pp * pp + b * pp + c;

        while(fr +  <= to && s(q[to], q[to - ]) <= s(i, q[to - ])) to --;

        q[++ to]=i;

    }

    printf("%lld\n", dp[n]);

    return ;

}