#include <iostream>
#include <set>
#include <cstring>
using namespace std;
typedef struct
{
char grid[7];
} wrap;
bool compare(wrap w1, wrap w2)
{
return strcmp(w1.grid, w2.grid) == -1;
}
set <wrap, bool(*)(wrap, wrap)> myset(compare);
int main() {
wrap w1 { "abcdef" };
wrap w2 { "ABCDEF" };
myset.insert(w1);
myset.insert(w2);
std::cout << myset.begin()->grid[0] << '\n';
}
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