BLOPER.cpp

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

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n, sum;
    cin >> n >> sum;
    int s = n * (n + 1) / 2;
    int diff = s - sum;
    if (sum > s || sum < 2 - s || diff % 2 || diff == 2) {
        cout << "Impossible" << '\n';
        return 0;
    }
    diff /= 2;
    diff -= 2;
    vector<bool> res(max(n, 4) + 1, false);
    for (int i = n; i >= 5; i--) {
        if (diff >= i) {
            diff -= i;
            res[i] = true;
        }
    }
    switch (diff) {
        case 0:
            res[2] = true;
            break;
        case 1:
            res[3] = true;
            break;
        case 2:
            res[4] = true;
            break;
        case 3:
            res[2] = true;
            res[3] = true;
            break;
        case 4:
            res[2] = true;
            res[4] = true;
            break;
        case 5:
            res[3] = true;
            res[4] = true;
            break;
        case 6:
            cout << "Impossible" << '\n';
            return 0;
        case 7:
            res[2] = true;
            res[3] = true;
            res[4] = true;
    }
    cout << '1';
    for (int i = 2; i <= n; i++) {
        if (res[i]) cout << '-';
        else cout << '+';
        cout << i;
    }
    cout << '\n';
}