干

Don't confuse with

干 (gàn, to do/dry) has two flat horizontal strokes crossed by a straight vertical line that pokes out above the top one, like a signpost. 千 (qiān, thousand) swaps that vertical for a diagonal stroke slanting down from the top-left, sitting above a cross shape. 于 (yú, at/in) keeps two horizontals too, but the "vertical" is really a hook that curls under the bottom line and never pokes above the top — quieter and more closed than 干.