#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N=35003;
int a[N],first[N],last[N],pre[N],dp[N];
ll b[N],dat[N << 2], cov[N << 2];
void inline pushup(int p)
{
    dat[p] = min(dat[p << 1], dat[(p << 1) | 1]);
}
void build(int p, int l, int r)
{
    dat[p] = cov[p] = 0;
    if (l == r)
    {
        dat[p] = b[l];
        return;
    }
    int mid = (l + r) >> 1;
    build(p << 1, l, mid);
    build((p << 1) | 1, mid + 1, r);
    pushup(p);
}
void pushdown(int p, int l, int r)
{
    if (cov[p])
    {
        int mid = (l + r) >> 1;
        dat[p << 1] += cov[p];
        cov[p << 1] += cov[p];
        dat[(p << 1) | 1] += cov[p];
        cov[(p << 1) | 1] += cov[p];
        cov[p] = 0;
    }
}
void change(int p, int l, int r, int ql, int qr, int x)
{
    if (ql <= l && r <= qr)
    {
        dat[p] += x;
        cov[p] += x;
        return;
    }
    pushdown(p, l, r);
    int mid = (l + r) >> 1;
    if (ql <= mid)
        change(p << 1, l, mid, ql, qr, x);
    if (qr > mid)
        change((p << 1) | 1, mid + 1, r, ql, qr, x);
    pushup(p);
}
ll ask(int p, int l, int r, int ql, int qr)
{
    if (ql <= l && r <= qr)
        return dat[p];
    pushdown(p, l, r);
    int mid = (l + r) >> 1;
    ll ret = 1e18;
    if (ql <= mid)
        ret = min(ret,ask(p << 1, l, mid, ql, qr));
    if (qr > mid)
        ret = min(ret,ask((p << 1) | 1, mid + 1, r, ql, qr));
    return ret;
}
int main()
{
    int n,m;
    scanf("%d%d",&n,&m);
    for (int i = 1; i <= n; i++)
    {
        scanf("%d",a + i);
        b[i] = b[i-1];
        if (last[a[i]])
            pre[i]=last[a[i]],b[i]+=i-pre[i];
        else
            pre[i]=i,first[a[i]]=i;
        last[a[i]] = i;
    }
    for (int t = 1; t < m; t++)
    {
        build(1,t,n);
        for (int i = t + 1; i <= n; i++)
        {
            if (i!=pre[i]&&pre[i]>t)
                change(1,t,n,t,max(t,pre[i]-1),i-pre[i]);
            b[i]=ask(1,t,n,t,i-1);
            // printf("%lld ",b[i]);
        }
        // printf("\n");
    }
    printf("%lld\n",b[n]);
    return 0;
}