#include<bits/stdc++.h> using namespace std; int main() { char a[256]; cin>>a; for(int i=0;i<=strlen(a);i++){ if(a[i]=='A') a[i]='T'; else if(a[i]=='T') a[i]='A'; else if(a[i]=='C') a[i]='G'; else if(a[i]=='G') a[i]='C'; } cout<<a; }