/*#include<cstring>#include<algorithm>#include<queue>#include<vector>#include<cstdio>#include<cmath>#include<iostream>*/

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int maxn = ;

int main()

{

        int k, n, s, p;

        cin >> k >> n >> s >> p;

        int ans = n / s + ( - (n % s == ));

        ans *= k;

        cout << ans / p + ( - (ans % p == )) << endl;

        return ;

}

/*#include<cstring>#include<algorithm>#include<queue>#include<vector>#include<cstdio>#include<cmath>#include<iostream>*/

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int maxn = ;

char f[][];

int ans;

int aimc = ;

int aimr = ;

int flag;

int now;

int main()

{

        int n, k;

        cin >> n >> k;

        for (int i = ; i <= n; i++)

        {

                scanf("%s", f[i] + );

        }

        for (int i = ; i <= n; i++)

        {

                for (int j = ; j <= n; j++)

                {

                        if (f[i][j] == '#')

                        {

                                continue;

                        }

                        now = ;

                        for (int dx = j - k + ; dx <= j; dx++)

                        {

                                if (dx + k > n + )

                                {

                                        break;

                                }

                                if (dx < )

                                {

                                        continue;

                                }

                                flag = ;

                                for (int w = dx; w <= dx + k - ; w++)

                                {

                                        if (f[i][w] == '#')

                                        {

                                                flag = ;

                                                break;

                                        }

                                }

                                if (flag)

                                {

                                        now++;

                                }

                        }

                        for (int dy = i - k + ; dy <= i; dy++)

                        {

                                if (dy + k > n + )

                                {

                                        break;

                                }

                                if (dy < )

                                {

                                        continue;

                                }

                                flag = ;

                                for (int w = dy; w <= dy + k - ; w++)

                                {

                                        if (f[w][j] == '#')

                                        {

                                                flag = ;

                                                break;

                                        }

                                }

                                if (flag)

                                {

                                        now++;

                                }

                        }

                        if (now > ans)

                        {

                                ans = now;

                                aimc = i, aimr = j;

                        }

                }

        }

        cout << aimc << " " << aimr << endl;

        return ;

}

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

int main()

{

        ll n,k,m,d;

        cin >> n >> k >> m >> d;

        ll anser=;

        for(ll i=;i<=d;i++)

        {

                if(i!=)

                {

                        ll now=n/(i-);

                        if(now<k)

                        continue;

                }

                ll sum=n/(k*i-k+);

                if(sum>m)

                {

                        if(m*i>=(n-n%m)/k)

                        sum=m;

                        else

                        continue;

                }

                anser=max(anser,sum*i);

        }

        cout<<anser<<endl;

        return ;

}

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

int a[];

int main()

{

        int n, l;

        cin >> n >> l;

        n--;

        int minn = INT_MAX;

        int sum = ;

        for (int i = ; i < n; i++)

        {

                cin >> a[i];

        }

        for (int i = ; i < l; i++)

        {

                sum += a[i];

        }

        minn = sum;

        for (int i = l; i <= n - ; i++)

        {

                sum -= a[i - l];

                sum += a[i];

                minn = min(minn, sum);

        }

        cout << minn << endl;

        return ;

}