#include <bits/stdc++.h>
#define ll long long
#define mp make_pair
#define fi first
#define se second
#define pb push_back
#define pi pair<int, int>
#define mod 1000000007
template<typename T> bool chkmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
ll ksm(ll a, ll b) {if (b == 0) return 1; ll ns = ksm(a, b >> 1); ns = ns * ns % mod; if (b & 1) ns = ns * a % mod; return ns;}
using namespace std;
const int maxn = 100005;
int n;
int k; // can decr at most k times
int a[maxn], decr[maxn]; //
int md[maxn];

struct ST {
    int l, r;
    ST *ch[2];
    ll mx, lz; // lz : plus mx : range max
    ll mxr; // max after the mxdecr
    pi mxdecr; // first: value second: place
    pi rec; // right most
}p[maxn << 1], *root;
int stcnt = 0;
void bdtree(ST *a, int l, int r) {
    a->l = l, a->r = r;
    a->mx = a->lz = 0; a->mxdecr = mp(0, r);
    a->mxr = 0, a->rec = mp(0, r);
    if (l == r) return ;
    int mid = (l + r) >> 1;
    a->ch[0] = &p[stcnt++], a->ch[1] = &p[stcnt++];
    bdtree(a->ch[0], l, mid), bdtree(a->ch[1], mid + 1, r);
}
void upd(ST *a) {
    a->mx = max(a->ch[0]->mx, a->ch[1]->mx);
    a->mxdecr = max(a->ch[0]->mxdecr, a->ch[1]->mxdecr);
    if (a->mxdecr == a->ch[1]->mxdecr)
        a->mxr = a->ch[1]->mxr;
    else 
        a->mxr = max(a->ch[1]->mx, a->ch[0]->mxr);
    a->rec = a->ch[1]->rec;
}
void actlz(ST *a, ll x) {
    a->lz += x;
    a->mx += x;
    a->mxr += x;
}
void pushdown(ST *a) {
    if (a->lz) {
        for (int i = 0; i < 2; i++)
            actlz(a->ch[i], a->lz);
        a->lz = 0;
    }
}
void push(ST *a, int l, int r, ll x) {
    if (a->l == l && a->r == r) {
        actlz(a, x);
        return ;
    }
    pushdown(a);
    int mid = (a->l + a->r) >> 1;
    if (r <= mid) push(a->ch[0], l, r, x);
    else if (l > mid) push(a->ch[1], l, r, x);
    else push(a->ch[0], l, mid, x), push(a->ch[1], mid + 1, r, x);
    upd(a);
}
void chd(ST *a, int pl, pi dc) {
    if (a->l == a->r) {
        a->mxdecr = dc;
        a->rec = dc;
        return ;
    }
    pushdown(a);
    int mid = (a->l + a->r) >> 1;
    if (pl <= mid) chd(a->ch[0], pl, dc);
    else chd(a->ch[1], pl, dc);
    upd(a);
}
ll qmx(ST *a, int l, int r) {
    if (a->l == l && a->r == r) return a->mx;
    pushdown(a);
    int mid = (a->l + a->r) >> 1;
    if (r <= mid) return qmx(a->ch[0], l, r);
    else if (l > mid) return qmx(a->ch[1], l, r);
    else return max(qmx(a->ch[0], l, mid), qmx(a->ch[1], mid + 1, r));
}
pi qdecr(ST *a, int l, int r) {
    if (a->l == l && a->r == r) return a->mxdecr;
    pushdown(a);
    int mid = (a->l + a->r) >> 1;
    if (r <= mid) return qdecr(a->ch[0], l, r);
    else if (l > mid) return qdecr(a->ch[1], l, r);
    else return max(qdecr(a->ch[0], l, mid), qdecr(a->ch[1], mid + 1, r));
}

ll nmx;
ll rch; pi rs;
int findlst(ST *a) {
    if (a->l == a->r) return a->l;
    pushdown(a);
    // check if in left
    pi cc = max(a->ch[0]->rec, a->ch[1]->mxdecr);
    int flag = 0; ll cur = rch;
    if (chkmax(cc, rs)) 
        flag = 1;
    else if (cc == a->ch[1]->mxdecr) 
        cur = max(cur, a->ch[1]->mxr);
    else 
        cur = max(cur, a->ch[1]->mx);
    if (cur <= max(0ll, nmx - cc.fi)) {
        chkmax(rch, a->ch[1]->mx);
        chkmax(rs, a->ch[1]->mxdecr);
        return findlst(a->ch[0]);
    }
    else return findlst(a->ch[1]);
}
int tp[maxn];
bool chk(ll x, int k) {
    stcnt = 0;
    root = &p[stcnt++];
    bdtree(root, 1, n + 1);
    memset(tp, 0, sizeof(tp));
    for (int i = 1; i <= n; i++) {
        push(root, 1, i, a[i]);
        chd(root, i, mp(decr[i], i));
        while (root->mx > x && k) {
            //cout << root->mx << ' ' << k << endl;
            nmx = root->mx;
            rch = 0, rs = mp(0, 0);
            int l = findlst(root);
            k--;
            if (l > 1 && qmx(root, l, i) <= root->mx - qdecr(root, l, i).fi)
                l -= 1;
            pi qd = qdecr(root, l, i);
            //cout << "UPD " << l << ' ' <<qd.se << ' ' << qd.fi << endl;
            tp[qd.se] = 1;
            push(root, 1, qd.se, -qd.fi);
            chd(root, qd.se, mp(0, qd.se));
        }
        if (root->mx > x) return 0;
    }
    return 1;
}
ll ans;
ll s[maxn];
ll cals() {
    ll sum = 0;
    ll pmn = 0;
    ll nans = 0;
    for (int i = 1; i <= n; i++) {
        sum += s[i];
        chkmin(pmn, sum);
        chkmax(nans, sum - pmn);
    }
    return nans;
}
void solve(int k) {
    // cout << k << endl;
    // for (int i = 1; i <= n; i++)
    //     cout << a[i] << ' ' << decr[i] << endl;
    // cout << chk(3, k) << endl;
    // while (1);
    ll l = 0, r = 1e15;
    while (l < r) {
        ll mid = (l + r) >> 1;
        if (chk(mid, k)) {
            for (int i = 1; i <= n; i++)
                s[i] = a[i] - tp[i] * decr[i];
            r = cals();
        }
        else l = mid + 1;
    }
    chk(l, k);
    ans = l;
    cout << l << endl;
    int cnt = 0;
    for (int i = 1; i <= n; i++) 
        cnt += tp[i];
    for (int i = 1; i <= n; i++)
        if (tp[i] == 0 && cnt < k && decr[i] >= 0)
            tp[i] = 1, cnt += 1;
}
int f[2][maxn];
int ntp[maxn];

int main() {  
    // freopen("3a(1).in", "r", stdin);
    // freopen("new.out", "w", stdout);
    cin >> n;
    int m;
    cin >> m;
    int base = 0;
    int cnt[2] = {0, 0};
    for (int i = 0; i < 2; i++)
        for (int j = 1; j <= n; j++) 
            scanf("%d", &f[i][j]);
    for (int i = 1; i <= n; i++) {
        if (f[0][i] <= f[1][i]) ntp[i] = 0;
        else ntp[i] = 1;
        cnt[ntp[i]] += 1;
    }
    if (cnt[0] > m) {
        base = 1;
        for (int i = 1; i <= n; i++)
            decr[i] = f[1][i] - f[0][i], a[i] = f[1][i];
        solve(m);
    }
    else {
        base = 0;
        for (int i = 1; i <= n; i++)
            decr[i] = f[0][i] - f[1][i], a[i] = f[0][i];
        solve(n - m);
    }
    for (int i = 1; i <= n; i++) {
        tp[i] ^= base;
        printf("%c", 'A' + tp[i]);
    }
    int tot = 0;
    for (int i = 1; i <= n; i++)
        tot += (tp[i] == 0);
    assert(tot == m);
    for (int i = 1; i <= n; i++)
        s[i] = f[tp[i]][i];
    assert(ans == cals());
    //cerr << 1.0 * clock() / CLOCKS_PER_SEC << endl;
    return (0-0); // <3 cxr
}