#include<bits/stdc++.h> using namespace std; int main(){ string s1,s2; cin>>s1; for(int i=0;i<s1.length();i++){ if(s1[i]=='T'){ s2[i]='A'; }else if(s1[i]=='A'){ s2[i]='T'; }else if(s1[i]=='C'){ s2[i]='G'; }else{ s2[i]='C'; } cout<<s2[i]; } return 0; }