#include <bits/stdc++.h>

using namespace std;

typedef long long i64;
const int BUFFER_SIZE = 1 << 20;
char rb[BUFFER_SIZE], *rp = rb, *rt = rb;
inline char read_char() {
    return rp == rt ? (rt = rb + fread(rb, 1, BUFFER_SIZE, stdin), rp = rb, *rp ++) : *rp ++;
}
inline i64 read_int() {
    i64 x = 0;
    char ch = read_char(), flag = 0;
    while (ch != '-' && (ch < '0' || ch > '9')) {
        ch = read_char();
    }
    if (ch == '-') {
        flag = 1;
        ch = read_char();
    }
    for (x = 0; ch >= '0' && ch <= '9'; ch = read_char()) {
        x = x * 10 + (ch - '0');
    }
    return flag ? -x : x;
}

const int MAX_N = 1000 + 5;
const int MAX_A = 1 << 13 | 5;

int N;
int a[MAX_N], sa[MAX_N];
bitset<MAX_A> f[MAX_N];
short fj[MAX_N][MAX_A];
char fc[MAX_N][MAX_A];
char ans[MAX_N];

int lowbit(int x) {
    return x & -x;
}
int highbit(int x) {
    return x ? 1 << 31 - __builtin_clz(x) : 0;
}

int main() {
    scanf("%d", &N);
    for (int i = 1; i <= N; i ++) {
        scanf("%d", &a[i]);
        sa[i] = sa[i - 1] + a[i];
    }
    if (sa[N] != lowbit(sa[N])) {
        printf("no\n");
        return 0;
    }
    f[0][0] = 1;
    for (int i = 0; i < N; i ++) {
        for (int j = 0; j <= sa[i]; j ++) {
            if (!f[i][j]) continue;
            int k = sa[i] - j;
            if (!j || lowbit(j) >= a[i + 1]) {
                int jj = j + a[i + 1], kk = k;
                int jh = highbit(jj), kh = highbit(kk);
                if (jh != kh) {
                    // printf("i=%d, j=%d,k=%d,a=%d, jj=%d\n", i, j, k, a[i + 1], jj);
                    f[i + 1][jj] = 1;
                    fj[i + 1][jj] = j;
                    fc[i + 1][jj] = 'l';
                } else {
                    // printf("i=%d, j=%d,k=%d,a=%d,  jh=%d,kh=%d\n", i, j, k, a[i + 1], jh, kh);
                    f[i + 1][jj - jh] = 1;
                    fj[i + 1][jj - jh] = j;
                    fc[i + 1][jj - jh] = 'l';
                    f[i + 1][jj + jh] = 1;
                    fj[i + 1][jj + jh] = j;
                    fc[i + 1][jj + jh] = 'l';
                }
            }
            if (!k || lowbit(k) >= a[i + 1]) {
                int jj = j, kk = k + a[i + 1];
                int jh = highbit(jj), kh = highbit(kk);
                if (jh != kh) {
                    // printf("i=%d, j=%d,k=%d,a=%d, jj=%d\n", i, j, k, a[i + 1], jj);
                    f[i + 1][jj] = 1;
                    fj[i + 1][jj] = j;
                    fc[i + 1][jj] = 'r';
                } else {
                    // printf("i=%d, j=%d,k=%d,a=%d,  jh=%d,kh=%d\n", i, j, k, a[i + 1], jh, kh);
                    f[i + 1][jj - jh] = 1;
                    fj[i + 1][jj - jh] = j;
                    fc[i + 1][jj - jh] = 'r';
                    f[i + 1][jj + jh] = 1;
                    fj[i + 1][jj + jh] = j;
                    fc[i + 1][jj + jh] = 'r';
                }
            }
        }
    }

    // for (int i = 0; i <= N; i ++) {
    //     for (int j = 0; j <= sa[i]; j ++) {
    //         printf("%d", (int)f[i][j]);
    //         if (f[i][j]) printf("(%d%c)", (int)fj[i][j], fc[i][j]);
    //     }
    //     printf("\n");
    // }

    int J = -1;
    if (f[N][0]) {
        J = 0;
    } else if (sa[N] > 1 && f[N][sa[N] / 2]) {
        J = sa[N] / 2;
    } else if (f[N][sa[N]]) {
        J = sa[N];
    }
    if (J == -1) {
        printf("no\n");
        return 0;
    }
    int JJ = J;

    for (int i = N; i >= 1;i --) {
        if (!f[i][J]) {
            printf("gg f[i][J]=0\n");
            exit(0);
        }
        ans[i] = fc[i][J];
        J = fj[i][J];
    }
    assert(strlen(ans + 1) == N);

    deque<int> q;
    for (int i = 1; i <= N; i ++) {
        int t = a[i];
        if (ans[i] == 'l') {
            for (; q.size() && q.front() == t; q.pop_front()) t *= 2;
            q.push_front(t);
        } else {
            for (; q.size() && q.back() == t; q.pop_back()) t *= 2;
            q.push_back(t);
        }
    }
    assert(q.size() == 1);
    printf("%s\n", ans + 1);
    return 0;
}