#include <bits/stdc++.h>
using namespace std;
const int N = 305; 
char c[N];
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];
	}
	cout << endl;
	return 0;
}
//🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯🌯

#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;
}