#include<iostream>
using namespace std;

int main(){
    int n,s;
    cin>>n>>s;
    int total=0;
    while (n--){
        string st;cin>>st;
        if(st.size()==1){
            total+=st[0]-'0';
        }
        else{
            total+=st[0]-'0';
            total+=1;
        }
    }

    (total%s)-1==-1?cout<<0:cout<<(total%s)-1;


    return 0;
}//