#include <iostream> #include <string> using namespace std; string getComplement(const string& dna) { string complement; for (char base : dna) { switch (base) { case 'A': complement += 'T'; break; case 'T': complement += 'A'; break; case 'G': complement += 'C'; break; case 'C': complement += 'G'; break; } } return complement; } int main() { string dna; cin >> dna; cout << getComplement(dna) << endl; return 0; }