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import std.algorithm.iteration;
import std.algorithm.sorting;
import std.stdio;
import std.typecons;
void main()
{
Tuple!(string, int)[] arr = [tuple("a", 1), tuple("a", -1), tuple("b", 2), tuple("b", 25), tuple("c", 100), tuple("b", 21)];
arr.sort!("a[0] > b[0]").chunkBy!((a, b) => a[0] == b[0]).each!writeln;
}