#include <bits/stdc++.h>

#define loop(v, f, l) for(int v = (f), v##_ = (l); v < v##_; ++v)

using namespace std;

typedef long long int lint;
static inline int in(){ int x; scanf("%d", &x); return (x); }
static inline lint inl(){ lint x; scanf("%lld", &x); return (x); }

int main()
{
	int candy;
	while( scanf("%d", &candy) != EOF )
	{
		printf("3C%02d\n", (candy - 1) % 39 + 1);
	}
	return (0);
}