#include <cstdio> #include <cstring> #include <iostream> #include <string> #include <cmath> #include <bitset> #include <vector> #include <map> #include <set> #include <queue> #include <deque> #include <algorithm> #include <complex> #include <unordered_map> #include <unordered_set> #include <random> #include <cassert> #include <fstream> #include <utility> #include <functional> #include <time.h> #include <stack> #include <array> #define popcount __builtin_popcount using namespace std; typedef long long int ll; typedef pair<int, int> P; int dp[5050][5050]; int s1[5050][5050]; int s2[5050][5050]; ll a[5050]; ll s[5050]; int n; ll x; int main() { int n; ll x; cin>>n>>x; for(int i=0; i<n; i++){ cin>>a[i]; s[i+1]=s[i]+a[i]; } for(int i=0; i<n; i++) dp[i][i]=1; for(int d=1; d<n; d++){ for(int i=0; i+d<n; i++){ int l=i, r=i+d; int k=upper_bound(s, s+n+1, s[l]+x)-s; k-=2; k=min(k, r-1); if(s1[l+1][r]-s1[k+2][r]>0){ dp[l][r]=0; s1[l][r]=s1[l+1][r]+dp[l][r]; s2[l][r]=s2[l][r-1]+dp[l][r]; continue; } k=lower_bound(s, s+n+1, s[r+1]-x)-s; k=max(k, l+1); if(s2[l][r-1]-s2[l][k-2]>0){ dp[l][r]=0; }else{ dp[l][r]=1; } s1[l][r]=s1[l+1][r]+dp[l][r]; s2[l][r]=s2[l][r-1]+dp[l][r]; } } if(dp[0][n-1]) cout<<"B"<<endl; else cout<<"A"<<endl; return 0; }