#include <string>
class Solution {
public:
    string compressString(string param) {
        // write code here
        string ans;
        int n = param.size();
        int k = 1;
        ans += param[0];
        for(int i = 1; i < n; i++){
            if(param[i] == param[i - 1]){
                k++;
            }
            else {
                if(k != 1) 
                ans += to_string(k);
                k = 1;
                ans += param[i];
            }
        }
        if(k != 1) ans += to_string(k); 
        return ans;
    }
};