#include <iostream>
#include <cstring>
using namespace std;
int main() {
int va[6];
char s[256];
cin.getline(s, 256);
int i = 0;
while (s[i] != '\0') {
if (s[i] == 'a' || s[i] == 'A')
va[1]++;
else if (s[i] == 'e' || s[i] == 'E')
va[2]++;
else if (s[i] == 'i' || s[i] == 'I')
va[3]++;
else if (s[i] == 'o' || s[i] == 'O')
va[4]++;
else if (s[i] == 'u' || s[i] == 'U')
va[5]++;
i++;
}
int max = 0, k = 0;
for (int i = 1; i <= 5; ++i) {
if (f[i] > max)
max = f[i], k = i;
}
if (k == 1)
cout << 'A';
if (k == 2)
cout << 'E';
if (k == 3)
cout << 'I';
if (k == 4)
cout << 'O';
if (k == 5)
cout << 'U';
return 0;
}
