Compute it just as the problem statement instructs.

First, receive an input as a string type (like string in C++); let call this \(S\).

Since the last letter of \(S\) represents \(Y\), so store \(Y\).

The last two characters of \(S\) is unnecessary for the output; delete it.

Then,

• append - to \(S\) if \(0 \leq Y \leq 2\);
• append + to \(S\) if \(7 \leq Y \leq 9\).

Finally, output \(S\).

Sample code in C++:

#include<bits/stdc++.h>
using namespace std;

signed main(){
    string s;
    cin>>s;

    int n=s.size();//let n be the length of s
    int y=s[n-1]-'0';

    s=s.substr(0,n-2);
    // obtain (n-2) consecutive characters, beginning from the 0-th character, from s; that is, remove the last two characters.

    if(y<=2){
        s+='-';
    }else if(y>=7){
        s+='+';
    }

    cout<<s<<endl;

    return 0;
}