Osajono

input/code.cpp:5:1: error: specializing member 'std::basic_ios<char>::sync_with_stdio' requires 'template<>' syntax
 ios::sync_with_stdio(false);
 ^

#include <iostream>

using namespace std;

ios::sync_with_stdio(false);

int main() {

    int n;
    cin >> n;

    char s[n];
    for (int i=0; i<n; ++i) {
        cin >> s[i];
    }
    int c = n;
    for (int i=0; i<n; ++i) {
        for (int j=i+1; j<n; ++j) {
            if (s[i]==s[j]) ++c;
        }
    }

    cout << c;
}