#include <iostream>
#include <string>
using namespace std;
void displayMidfix(const std::string &a)
{
size_t length = a.length();
size_t middle = length/2;
string c = a.substr(middle-1, 3);
cout << "Midfix: " << c << endl;
}
int main()
{
string a;
while (cin >> a) {
displayMidfix(a);
}
return 0;
}
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