题解

#include <iostream>
#include <string>
using namespace std;

int main() {
string a;
cin >> a;
int b[26] = {0};
for (char c : a) {
b[c - 'a'];
}
for (int i = 0; i < 26; i) {
if (b[i] > 0) {
cout << char('a' + i) << ":" << b[i] << endl;
}
}

return 0;

}