int main()
{
string s;
vector<int> nums;
cin >> s;
int window = s[s.size() - 1] - '0';
int temp = 0;
for (int i = 0; i < s.size() - 1; ++i)
{
if (s[i] == ',' || s[i] == ':')
{
nums. push_back(temp);
temp = 0;
continue;
}
temp = temp * 10 + (s[i] - '0');
}
int left = 0;
int right = window - 1;
double mid = Mean(left, right, nums, window);
double p = -10000;
left++;
right++;
while (right != nums.size())
{
p = Max(p, (Mean(left, right, nums, window) - mid) / mid);
mid = Mean(left, right, nums, window);
left++;
right++;
}
double help = 100;
double result = p *help;
cout << setiosflags(ios::fixed) << setprecision(2);
cout << result << "%" << endl;
return 0;
}
