#include <iostream> 
#include <cstring>
#include <string>
using namespace std;
int main(){
	string str;
	cin>>str;
	int n=str.size();
	for(int i=0;i<n;i++){//A跟T配对,G跟C配对 
	    if(str[i]=='A'&&str[i+1]=='T')str[i]=str[i+1];
	    
		if(str[i]=='T'&&str[i+1]=='A')str[i+1]=str[i];
		
		if(str[i]=='G'&&str[i+1]=='C')str[i]=str[i+1];
		
	    if(str[i]=='C'&&str[i+1]=='G')str[i]=str[i+1];    	
	}
	for(int i=0;i<n;i++){
		cout<<str[i];
	}
	return 0;
}