https://pintia.cn/problem-sets/994805260223102976/problems/994805280817135616
#include <iostream>
using namespace std;
int main(){
string s;
getline(cin, s);
char c;
int cnt = 0, count[200] = {0};
for(int i = 0; i < s.size(); i++){
if(s[i] <= 'Z' && s[i] >= 'A')
s[i] = s[i] - 'A' + 'a';
count[s[i]]++;
if(cnt < count[s[i]] && s[i] <= 'z' && s[i] >= 'a'){
c = s[i];
cnt = count[s[i]];
}else if(cnt == count[s[i]] && s[i] <= 'z' && s[i] >= 'a'){
if(c > s[i]) c = s[i];
}
}
cout << c << " " << cnt;
return 0;
}