STONES

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

const int N = 1005;

int n, m;
int a[N];

void solve() {
    a[0] = 0;
    for(int i = 1; i <= n; ++i)
        if(a[i] == -1) {
            a[i] = a[i-1] + m;
        }

    for(int i = 1; i <= n; ++i)
        if(a[i] - a[i-1] < m) {
            cout << -1 << ' ';
            return;
        }

    for(int i = 1; i <= n; ++i)
        cout << a[i] - a[i-1] << ' ';

}

int main() {
    //freopen("in.txt", "r", stdin);
    freopen("STONES.inp", "r", stdin);
    freopen("STONES.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);

    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
        cin >> a[i];

    solve();

    return 0;
}