#include<bits/stdc++.h>
using namespace std;
string str;
void solve(){
    while(cin>>str){
        string tmp;
        for(char &ch:str){
            if(isupper(ch)){
                tmp.push_back('_');
                tmp.push_back(ch+32);
            }else{
                tmp.push_back(ch);
            }
        }
        cout<<tmp<<"\n";
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);  
    solve();
    return 0;
}