Stamps 100

You are given a **binary** string $S$ of length $N$. You can apply the following operation any (possibly zero) number of times: - Select an integer $i\ \lparen 1 \leq i \leq N-2 \rparen$ and replace the substring $S_i S_{i+1} S_{i+2}$ with `100`. Find the **lexicographically smallest** string after the operations. Note: String $X$ is lexicographically smaller than string $Y$ if $X_i \lt Y_i$, w