#include<bits/stdc++.h>
using namespace std;
#define pint pair<int,int>
#define fir first
#define sec second
#define lowbit(i) (i&-i)
int n,a[1010];
map<pint,pair<pint,bool>>dp[1010];
inline void merge(int &x,int &y){
	for(int i=13;~i;--i){
		if((x>>i)&1){
			if((y>>i)&1) x+=(1<<i),y-=(1<<i);
			return;
		}if((y>>i)&1) return;
	}
}inline void print(int id,pint spt){
	if(!id) return;
	print(id-1,dp[id][spt].fir);
	cout<<(dp[id][spt].sec?'r':'l');
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	cin>>n;for(int i=1;i<=n;++i) cin>>a[i];
	int all=0;for(int i=1;i<=n;++i) all+=a[i];
	if(__builtin_popcount(all)!=1){cout<<"no"<<endl;return 0;}
	if(n<=20){
		bool flag=false;
		for(int base=0;base<(1<<n);++base){
			deque<int>spt;
			for(int i=0;i<n;++i){
				if((base>>i)&1) spt.push_front(a[i+1]);
				else spt.push_back(a[i+1]);
				while(spt.size()>=2&&spt[0]==spt[1])
					spt.pop_front(),spt.front()<<=1;
				while(spt.size()>=2&&spt.back()==spt[spt.size()-2])
					spt.pop_back(),spt.back()<<=1;
			}if(spt.size()==1){
				flag=true;
				for(int i=0;i<n;++i) cout<<((base>>i)&1?'r':'l');
				cout<<endl;
				break;
			}
		}if(!flag) cout<<"no"<<endl;
		return 0;
	}dp[0][{0,0}]={{0,0},0};
	for(int i=1;i<=n;++i)
	for(auto it=dp[i-1].begin();it!=dp[i-1].end();++it){
		pint spt=it->fir;
		if(!spt.fir||lowbit(spt.fir)>=a[i]){
			pint jev={spt.fir+a[i],spt.sec};
			merge(jev.fir,jev.sec);
			dp[i][jev]={spt,0};
		}if(!spt.sec||lowbit(spt.sec)>=a[i]){
			pint jev={spt.fir,spt.sec+a[i]};
			merge(jev.fir,jev.sec);
			dp[i][jev]={spt,1};
		}
	}if(dp[n].count({all,0}))
		print(n,{all,0}),cout<<endl;
	else if(dp[n].count({0,all}))
		print(n,{0,all}),cout<<endl;
	else cout<<"no"<<endl;
	return 0;
}