#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <algorithm>
using namespace std;

template <typename Tp> inline void getint(Tp &num){
	register int ch, neg = 0;
	while(!isdigit(ch = getchar())) if(ch == '-') neg = 1;
	num = ch & 15;
	while(isdigit(ch = getchar())) num = num * 10 + (ch & 15);
	if(neg) num = -num;
}

int N, K;

int main(){
	getint(N), getint(K);
	return printf("%d\n", N - K + 1), 0;
}

// A - Rated for Me
#include <bits/stdc++.h>
using namespace std;

int main(){
	int r; cin>>r;
	if(r < 1200) puts("ABC");
	else if(2800 <= r) puts("AGC");
	else puts("ARC");
}
