#include <bits/stdc++.h> using namespace std; char c[305]; int main() { string a; cin >> a; int n = a.size(); for (int i = 0; i < n; ++i) { switch (a[i]) { case 'A': c[i] = 'T'; break; case 'T': c[i] = 'A'; break; case 'G': c[i] = 'C'; break; case 'C': c[i] = 'G'; break; default: break; } } for (int i = 0; i < n; ++i) { cout << c[i]; } return 0; }