/**

public static char[] a= new char[20];

public static int ans = 0;

public static void dfs(int cur, int dian, int hua, int jiu) {

if(dian > 5)

return;

if(hua > 10)

return;

if(cur == 15) {

if(dian == 5 && hua == 10 && a[14] == 'b' && jiu == 0) {

for(int i = 0; i <= 14; i++)

System.out.print(a[i]);

System.out.println();

ans++;

}

return;

}

a[cur] = 'a';

dfs(cur+1, dian+1, hua, jiu*2);

a[cur] = 'b';

dfs(cur+1, dian, hua+1, jiu-1);

}

public static void main(String[] args) {

// TODO Auto-generated method stub

dfs(0, 0, 0, 2);

System.out.println(ans);

}