How to prevent blocks from going outside the container?

Question

css

Good afternoon, I have a flexbox container (green), inside of which there are five blocks

.green {
    display: flex;
    flex-flow: column wrap;
    height: auto;
    max-height: 1000px;
}

when the page height decreases, the blocks go to the right and a vertical scroll appears. The

question is, how can I make sure that all the blocks remain in place?