#include <stdio.h>

int main()
{
    char str[255];
    char ch;
    int i = 0;
    while((ch = getchar())!='\n'&& i<255)
    {
        if (ch=='A')
        str[i] = 'T';
        else if (ch=='T')
        str[i] = 'A';
        else if (ch=='G')
        str[i] = 'C';
        else
        str[i] = 'G';
        i++;
    }
    str[i] = '\0';
    printf("%s",str);
    return 0;
}```