#include <cstdio>

char S[1<<19];   // 262144
int n;
void solve(int k, int s)
{
    int sum = 0;
    if( s == 1 ){ printf("%c", S[k]); return; }
    for(int i = k ; i < k+s ; i++ )
        sum += (S[i]-'0');
    if( sum == 0 || sum == s ) printf("%d", (bool)sum);
    else{
        printf("-");
        solve(k, s/2);
        solve(k+s/2, s/2);
    }
}
int main()
{
    char in[100], out[100];
    for(int i = 1 ; i <= 20 ; i++ )
    {
        sprintf(in,".%d.in",i);
        sprintf(out,".%d.out",i);
        freopen(in,"r",stdin);
        freopen(out,"w",stdout);
        scanf("%d%s", &n, S);
        solve(0,n);
    }
}